Major Weather change expected in Central,Southern India

METD WEATHER
Akshay Deoras
Severe Weather Forecaster,

Nagpur recorded a minimum temperature of 6.3C on Wednesday,26th Dec 2012. However there is going to be a major weather change in the coming days in India

Bay Low Pressure system-

Attached is the 850mb GFS Map of Base 00z,28th Dec.

One can see a broad patch of anti-clockwise winds with green shading across Sri Lanka. This is the Bay low pressure system which shall pump moisture across mainland of India resulting into precipitation in the southern states-

Above is the +48hr precipitation forecast showing rainfall across Kerala,Tamil Nadu,Coastal Andhra Pradesh and some interior Karnataka.
The precipitation shall increase across Karnataka coastal areas eventually spreading into Goa on the New Year eve

If does appear that Goa may get light rain spell on 30th Dec 2012 and some on 31st Dec as well. The meteograms aren't agreeing however..

As the Bay system progresses westwards, a High Pressure system is expected to develop across Orissa at the 850mb level which shall steer the moisture and push it Northwards.

Minimum temperature in Central India will be rising nowonwards as the direction of the winds have changed.

The precipitation will spread into Southern Maharashtra with areas like Pune and subsequent interior Western Maharashtra will receive rains with rise in minimum temperature.
This shall happen on Monday,31st Dec 2012.

Pune which witnessed a min temperature around 7C shall have relatively warmer nights though a heavy rainfall event is unlikely due to the scattered precipitation tendency there..

As the moisture pumps further, it shall weaken in terms of Relative Humidity (RH) however be that much to bring cloudy skies in Nagpur and Central India.

The min temperatures will rise to around 15-17C in Nagpur taking away the winter effect in the city. Due to moisture amounts and slight unstable atmosphere, clouding shall be there in the city during ( Partial) 31st Dec and then increasing on 1st and 2nd Dec ( As of present GFS).

However, there seems to be a little problem with the initial Skew-T of that period

Above is the 1st Jan 2013 SKEW-T for Nagpur region. Its clearly visible in those indices that CAP or CIN will be greater than the CAPE ( CIN = 102 J/Kg)..
This situation depicts a non buoyant atmosphere where due to thermal inversion, buoyancy is lost thus a parcel of air ( moisture embedded) will sink as it rises due to which chance of convection and thunderstorm looks minimal now
However, the SKEW-T can change and moreover such CAP can break if there is abundant sunshine in the morning on the 1st Jan.

Situation on this rainfall event shall be more clear in the coming period

GFS shows a precipitation in Nagpur ( which then must be non convective) on 1st and 2nd Jan

Trace Amt rain can be expected on 31st Dec night ( As of 28th Dec GFS)

STAY TUNED FOR UPDATES AND FOLLOW METD WEATHER FACBOOK FOR MORE DETAILS--

Another powerful Western Disturbance all set to impact North India

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

Another powerful western disturbance is arriving towards North India. The 12z,11th Dec forecast models are indicating that the resulting precipitation (Although snowfall was reported in some stations of Himachal Pradesh today) will initiate from Wednesday,12th Dec 2012 ( a perfect 12-12-12) and will continue till around 15th Dec morning with the peak of the activity on Thursday,13th Dec 2012

Above- The GFS 700mb precipitation for 72hr (13th Dec 2012).

The change which is appearing from this simulation is that the precipitation ( in terms of snow and rain) shall be heavier towards the Himachal Pradesh,Uttarakhand side as compared to Jammu and Kashmir

Thus the snowfall shall be heavier in Himachal Pradesh than Jammu and Kashmir but it doesnt meant that J&K will not get a heavy snowfall event. Below is the expected scenario

* HEAVY SNOWFALL EXPECTED IN JAMMU AND KASHMIR,HIMACHAL PRADESH,UTTARAKHAND FROM 12TH DEC TO 14TH DEC WITH THE PEAK ON 13TH DEC

* DISRUPTIONS OF TRAFFIC POSSIBLE ON THE JAMMU-SRINAGAR HIGHWAY,SRINAGAR-LEH HIGHWAY ( ROAD ALREADY CLOSED)

*SRINAGAR CITY MAY FINALLY SEE A SNOWFALL ON 13TH DEC 2012

* GULMARG,SONAMARG,PAHALGAM TO WITNESS HEAVY SNOWFALL

* SHIMLA,MANALI AND OTHER CITIES OF HIMACHAL PRADESH TO RECEIVE VERY HEAVY SNOWFALL AND GREATER SNOW ACCUMULATIONS 

* RAINFALL EXPECTED ACROSS NORTH INDIAN PLAINS ESPECIALLY PUNJAB,HARYANA,UTTARAKHAND,HIMACHAL PRADESH

* DELHI,NCR MAY GET ISOLATED THUNDERSHOWERS DURING THE PERIOD. 

IF ANYONE WANTS TO SUBMIT THE SNOW IMAGES THEN THE IMAGES ( WITH DETAILS LIKE LOCATION,TIME OF IMAGE) MUST BE MAILED TO 

metdweather@live.com
OR 
SUBMIT ON FACEBOOK-

facebook.com/deorasakshay

THE IMAGES WILL BE PUBLISHED ON THE BLOG

Powerful Western Disturbance to impact North India bringing snowfall!

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

After a very prolonged gap, a powerful Western Disturbance will be striking North India from tomorrow onwards i.e 28th Nov 2012

Attached above is the 48hr projected base 00z,27th Nov 700mb vorticity coupled with the precipitation.. One can see that the rainfall amount will be very heavy (snowfall as well) in J&K prominently in Central,Western J&K.

With temperatures already in the freezing level, snowfall will happen on a heavy level basis in J&K and I suspect light to Moderate across Himachal Pradesh starting 28th Nov and continuing on reduced estimates on 29th Nov

Usually such western disturbances bring rains in Northern Plains like Punjab,Haryana,NCR New Delhi however with this setup, its unlikely that these regions will receive heavy rains.

On Thursday (29th Nov), I suspect some cloud cover for the Northern Plains with isolated rainfall chances (less chance though) which may not bring a much change in the weather

*** Srinagar City will also receive THE FIRST SNOWFALL OF THE SEASON ON 28TH NOV LATE PERIOD,29TH NOV. THIS SNOWFALL EVEN MAY CLOSE THE LEH-SRINAGAR HIGHWAY AROUND ZOJILA-PASS***

*** Jammu-Srinagar highway may also get traffic disruption*** 

GULMARG,SONAMARG,PAHALGAM ETC WILL BE DECORATED BY SNOW IN THIS EVENT***

RAINFALL EXPECTED IN OMAN,UAE-

Meanwhile another short wave trough shall arrive from Western regions coming over Saudi Arabia bringing rains around 29th Nov 2012 and then moving across UAE-Oman  brining rains there around 30th Nov 2012,1st Dec 2012

Thus cities like Muscat,Dubai etc will receive rains (along with parts like SE Oman) in this period

Folks from Muscat,Dubai can send the rainfall images to METD WEATHER on facebook
facebook.com/deorasakshay


STAY TUNED FOR UPDATES

Tropical Storm Nilam makes a landfall near Cuddalore

TS Nilam approaches Tamil Nadu. Landfall today afternoon

Arabian Sea system shows "signs" of life after models kill it! BOB Depression/TS to impact Tamil Nadu

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

Bay of Bengal Update- 

As was expected, the BOB system ( hence to be called as Tropical Depression) is churning in the Southern Bay of Bengal.

The above morning IR-BD imagery shows the exposed LLCC centred somewhere in the 9.5N,83.5E which is ~ 530km SE of Chennai.
So far the max sustained winds are around 55km/hr with MSLP ~ 1002mb.

The system has intensified since the last post due to favoured conditions. The model analysis suggests that the system is moving in a region of 30kt upper air divergence and around 15kt low level convergence with the V wind shear to be around 10kt.

Based on the models and observations, it appears that the system which at present is a Tropical Depression will INTENSIFY to a marginal Tropical Storm status ( With max sustained winds of around 65kt )

As a Tropical Storm, it shall head for a landfall in a region

 Between Ammapatam to Cuddalore ( Tamil Nadu) 

    ON Tuesday,Oct 30 2012 night period to Oct 31 2012 Wednesday early   morning hours- 

(10PM IST- 0400hrs IST) 

IMPACTS- 

* ROUGH SEA WILL CONTINUE NEAR THE TAMIL NADU COAST TILL 1ST NOV 2012 

* STRONG GUSTY WINDS WILL BE WITNESSED in ENTIRE TAMIL NADU, PONDICHERRY ( PUDUCHERRY),COASTAL BORDERING ANDHRA PRADESH BEGINNING TONIGHT AND ENDING AFTER THE SYSTEM PASSES

* HEAVY RAINS  ARE LIKELY IN THE AREAS IN CYCLONE's PATH AND ADJOINING AREAS AS SHOWN IN THE MAP AND THEN STRETCHING AS NORTH AS HYDERABAD on 31st Oct 2012 AS THE SYSTEM MOVES. MODERATE RAINS IN KARNATAKA AS WELL. 

* CHENNAI ALSO WILL WITNESS HEAVY RAINS,WINDS IN THE PERIOD 

* Flooding Potential across INTERIOR TAMIL NADU 

After the landfall, the depression will move inland and will be steered by the upper air winds which will move the system North-North East wards on Oct 31 due to which the rainfall shall spread into Karnataka,Andhra Pradesh,Maharashtra and the entire Eastern coastal states on 1-2nd Nov 2012. 

The rainfall then shall spread further reaching Northern Maharashtra-Central MP latitude by Nov 2-3 2012 due to which Nagpur will get rainfall in a period between 1-4th Nov 2012 with cloud skies. ( For exact details refer METD WEATHER FACEBOOK PAGE) with highest chances of rains on Nov 2-3. 

II- Arabian System- 

The recent GFS models have turned a lot since the last post and now they aren't showing any chance of Arabian System to form or it merging with the Bay Storm/Depression. 

Infact as was reported on METD WEATHER Facebook, the system faced a lot of problems on Oct 28th i.e yesterday as there was no proper low level convergence to grip the convection. 

However things changed today and lets have a look-

Animation- 

http://rammb.cira.colostate.edu/products/tc_realtime/loop.asp?product=4kmirimg&storm_identifier=IO962012&starting_image=2012IO96_4KMIRIMG_201210282200.GIF

Above- 

The top most image is of 28th Oct 0730GMT where the system faced a lot of problems due to lack of LL convergence. The below image is of Oct 29 0730GMT showing that the system has organised a lot since last 24hr given the developing Low level convergence of around 10kt. 

The system continues to remain in an excellent poleward outflow ( associated with the Bay system) of around 30kt and favoured SST to support robust convection. The wind shears are also relaxed (vertical). 

Here is a look at the latest precipitation embedded in the system- 

One can observe that outer rain bands have formed and there seems to be a developing LLCC with more banding from the Southern periphery of the system

Thus, I do expect that the Arabian Sea system will intensify further given the excellent conditions available. However, there is a decreasing confidence at the moment whether the system will head towards Gujarat or not. 

Considering the model runs and vicinity of the Bay system, it appears that the Arabian Sea system shall head NE gradually and move inland somewhere in Karnataka when the Bay system will be present. So in such a case, the chance of Arabian System forming into a Tropical Cyclone is very very less. However it can get converted into a Tropical Depression, move NE and move inwards in the Western Coast of India

As a result, the warnings issued previously for Gujarat STAND CANCELLED

TROPICAL CYCLONE/DEPRESSION ALERTS FOR INDIA

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

"THE TROPICAL CYCLONE/DEPRESSION ACTIVITY BOTH IN THE ARBIAN SEA AND BAY OF BENGAL IS EXPECTED. STORM TRACKS CAN THREATEN INDIA"

"" FOR THE LATEST UPDATES, FOLLOW METD WEATHER ON FACEBOOK"""

The flattened 2012 North Indian Ocean Cyclone Season has revived with two candidates. BOB 01 and Tropical Storm Murjan. As METD WEATHER doesn't consider it, lets not discuss those past systems.

I- Bay of Bengal ( BOB)

The above DUNDEE imagery ( IR) spectrum shows massive CB clouds in the Central BOB with cloud tops around -30C at the moment. The imagery is of 0530PM IST. 

Animation (IR) here shows how the system has evolved robustly. 

http://rammb.cira.colostate.edu/products/tc_realtime/loop.asp?product=4kmirimg&storm_identifier=WP932012&starting_image=2012WP93_4KMIRIMG_201210270900.GIF

The above imagery shows that the system has organised much as seen from its symmetrical geometry. The system is encountering a building ~10kt convergence at the lower levels with extremely favorable thermodynamic conditions. The system continues to have 20kt upper air divergence with relaxed wind shears (vertical of 05-10kt barely) to support cyclogenesis in the 28-30C SST in the region.

Considering the favoured conditions, it appears that the system is very likely to strengthen further in the next 48hrs before it approaches the Indian SE and Sri-Lanka coast. 

The system can advance further and get a "Tropical Storm" status in the next 48hrs...

Where will it head? 

As per the 12z model which has been consistent, the system will be heading West and will make a landfall in a region between Cuddalore,Tamil Nadu and Northern Sri Lanka region. The area is purposively being kept large to settle the landfall uncertainties.  

The landfall seems to be happening on Oct 30 2012 in the morning - afternoon time ***
*** time may change***

Potential Impacts-

* Rough Seas offshore Tamil Nadu will initiate within 48hrs and will increase as the system approaches. 

* Heavy Rains with strong winds shall initiate in the Eastern Tamil Nadu region from 29th Oct and increasing ( VERY HEAVY) during the landfall. 

-------------------------------

II- ARABIAN SEA

The above DUNDEE imagery showing a wedge region of convection in the Southern Arabian Sea. So far the region hasn't shown any significant convergence and hence the system continues to remain widespread in the Arabian Sea. 

However, as the Bay System ( Possibly will be named Tropical Storm Nilam) will interact with the Arabian System and due to this, the moisture amounts of the Arabian System will increase. 

As the Arabian System moves as per the estimated NW track due to the upper air wind pattern, it seems that system will intensify robustly ( Its having around 15kt lower convergence, 10kt upper air divergence, around 5-10kt vertical wind shear, favoured SST), 

This system has a very high chance of getting converted to a Tropical Storm and due to its path, Western India will face some rainfall events. 

At present, at the upper level a shortwave trough is digging through India and as the trough exits which eventually co-incides with the system's northerly approach, the system will be steered by the jet streams which will start the system turning NE towards India-Sindh region

Model uncertainty exists at the moment however considering the consistency and the upper air pattern, it appears that the system will make a landfall somewhere near NW Gujarat-Sindh border 

on Saturday,Nov 3 2012 *** 

*** timings will vary*** 

The region of landfall is purposively kept wide to avoid uncertainties of the models 

The probable landfall areas ( will be modified suitably)

Entire West Coastal Gujarat,Sindh coast. 

IMPACTS-

Rainfall shall happen across Western Coast of India ( excluding Kerala) with more amounts towards Goa,Western Maharashtra,NW Maharashtra, Central Maharashtra and vicinity. 

LAKSHADWEEP ALSO WILL GET  RAINS AS THE SYSTEM WILL APPROACH VERY CLOSE TO IT

Mumbai,Pune etc will get rains around 3-4th Nov period *** 

The landfall impacts shall vary with the storm's intensity hence it shall be notified later on. 

Rough seas shall persists near the Indian coasts

STAY TUNED FOR UPDATES

2012 WINTER FORECAST OF INDIA

(C) 2012 AKSHAY DEORAS

metdweather.blogspot.com

All Rights Reserved.....

2012 Winter Forecast of India

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

14th Oct 2012
0400hrs IST
Nagpur,India

Dear Readers,
The Official forecast for the 2012 Winter in India is below.

This year's forecast is an experimental forecast as we have used a new technique for weather forecasting. Till the last year, the winter forecast used to be made using the weather models directly. However there are many errors in it which ultimately spoil the forecast accuracy. This year's winter forecast consists of two parts. One is a technical part having all the scientific background for the forecast whereas the other one is the non technical or the public version for lucid understanding of the people.

As per the forecast, it appears that Northern half of the country will experience cooler than normal winter whereas southern half will experience warmer than normal conditions. As a result, the net forecast for 2012 Winter in India seems "NORMAL WINTER''

We also expect to cross the 2,00,000 pageviews after the Winter forecasts are published.

Thanks for the support !

For any feedback/suggestion, you can mail me at metdweather@live.com

Greetings!

Akshay Deoras

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List of topics-

1) Forecasting Basic
2) Current ENSO status,expected ENSO behaviour during 2012 Winter
3) Introduction to the Arctic Oscillation
4) **Relation between the Arctic Oscillation and Minimum temperatures during winter
5) Estimated Arctic Oscillation Index during 2012 Winter
6) The 2012 Winter Forecast
7) References & Acknowledgements

** We are introducing this relation for the first time 

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FORECASTING BASIC-

The South West Monsoon retreat is almost complete as the Sun is apparently shifting Southwards which plays a major role in the decrease in the average surface air temperature over Central and Northern India prominently. 

The Winter Forecast for India isn't restricted to the local weather phenomena which people believe i.e if there has been strong monsoon there will be good winter and vice versa. It has now been realized that the entire weather of India and many parts of the world is governed by the Global Weather Phenomena of El Nino Southern Oscillation happening in the Equatorial Central Pacific Ocean briefly. 

Though not fully understood, the phenomena is of oscillating sea surface temperatures in equatorial pacific regions between above normal,normal and below normal temperatures. The scientific reason is with the variation in the trade winds blowing eastward at the surface level which leads to changes in sea water level in some areas of Pacific Ocean like Indonesian coast, Australian Coast and offshore Peru.

The phases of ENSO are 

El Nino- When Sea Surface Temperature(SST) of Eq Pacific is warmer than normal

Neutral- When SST is normal

La Nina- When SST is cooler than normal in Eq.Pacific 

It has been widely observed that winters in India go comparatively cooler than normal during La Nina and warmer than normal during an El Nino. The reasons are still not known and aren't fully accepted by weather forecasters like me. 

In the 2010 Winter Forecast by METD WEATHER, we had postulated the  *** Jet Stream velocity vector variation with the ENSO as a parameter for forecasting the 2010 Winter Forecast as stated below.
The entire forecast can be seen here-

http://metdweather.blogspot.in/2010/11/2010-winter-forecast-for-india.html

"" La Nina also strengthens the Jet streams.

 Blocking high pressure over Tibet

As cooler temperature builds in Tibet, a high pressure area builds over Northern India and also in Tibet, Right now the air pressure is as high as 1040mb. The Jet streams flowing from west to east are blocked by this air pressure so the jet stream splits into two branches or mostly jet stream digs South instead of North

As the high pressure blocks the jet stream, jet stream digs southwards in India covering areas of Punjab,Haryana,Delhi,Madhya Pradesh,Maharashtra and much of the North-Central India.

The Jet rarely flows over Jammu and Kashmir ( except for Western Disturbance).

So more cool air digs southwards than normal during La Nina.

The intensity of the high pressure over Tibet and North India is related to the La Nina phenomena""


*** Jet Streams here refer to the Subtropical Jet Streams

In 2011, We continued with the La Nina- Jet Streams relation for forecasting the season. The forecast can be seen here

http://metdweather.blogspot.in/2011/10/2011-winter-forecast-of-india.html

"""Explanation to Cooling effect of La Nina

 A possible explanation which I think is the application of concept of intensified jet streams during la nina over Indian continent. 

La Nina is marked by the increased convection in west pacific than east pacific due to strong winds towards west and vice versa at the upper air. 

Thus an amplified subtropical jet stream will tend to bring more cold air in the Indian subcontinent particularly in Northern,Central and . In the case of El Nino, due to less amplified subtropical jet streams the blast of cool air is partial and it brings a noted warmer effect on the surface air temperatures. 

Example- A river is like ***Jet Stream. When the river's speed is greater it will drag the stones in its way. When speed is less, stones will not be carried with it. Stones can be compared with cold air.  """

*** Jet Streams here refer to the Subtropical Jet Streams

However it was later realised that the reasoning isn't sufficient to co-relate ENSO with Indian Winter and the forecasts showed strong anomaly when were compared with the actual conditions of 2010,2011. So we shall not consider this parameter in complete sense in this forecast.

In an attempt to establish the relationship between the Indian Winter with certain atmospheric oscillations, we came across the Arctic Oscillation (AO). We shall see the details regarding the AO-Winter interaction below

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2) Current ENSO status and expected ENSO behaviour in 2012 Winter

After a strong El Nino pattern which ended during early 2010, neutral conditions were observed for a few months after which La Nina pattern got established which continued through the 2010 winter and ended during summer of 2011. However a weak La Nina developed again and continued through the 2011 winter.

ENSO Neutral condition has been observed since then continuing even today.

Since  July end-August, probability of an El Nino emerging before the Northern Hemisphere winter was being considered as very high and the SST in the Equatorial Pacific Ocean tended towards a positive ( El Nino) phase.

Above- SST Anomaly as analysed on Aug 26 2012 shows a pool of warmer than normal SST ( in the red encircled region) in the vicinity of the Nino 3.4 region.

The July August September ( JAS) SST anomaly in the Nino 3.4 region was +0.3C

3-Month period      ONI  (C)
        MJJ                 0.0
        JJA                 0.1
        JAS                0.3      

But from September mid onwards, SST anomalies started decreasing ( approaching zero) in all the NINO regions including Nino 3.4.

The SST Anomaly analysed on 7th Oct 2012 is given below

  

One can observe that SST in the encircled region has cooled down as compared to the August 2012 situation.


The latest weekly SST departures are:
Niño 4      0.3ºC
Niño 3.4   0.1ºC
Niño 3     -0.1ºC
Niño 1+2  -0.1ºC

Thus one can infer that SST in the Central Pacific Ocean is turning towards a neutral and not towards the positive anomaly mode from September end. 

The 850mb winds in the Pacific Ocean which are a measure of the intensity of the Easterly Trade Winds are consistently showing anomalies ( westerly anomalies) across North Indonesia area. Easterly trade winds otherwise seem to be showing no anomaly and thus reducing the chance of an El Nino forming for a few more months.

The CPC considers a three month group SSTA in the ONI plots. So it can be expected that the ONI for August- Sept-Oct settles to around +0.40C

Above is the IRI Probabilistic ENSO Forecast. The forecast still calls for a 50% + chance for El Nino formation till DJF 2012-2013 period.

So according to our estimates, The ONI will be in the Neutral Range in the ASO period and shall hit the El Nino threshold of +0.5C in the SON period i.e El Nino Conditions may emerge around November end to December 2012 with a very weak amplitude.

So for those forecasters forecasting using the ENSO, it appears that more or less a ENSO Neutral will persists through the Northern Hemisphere winter with a slight El Nino conditions emerging in the year end.

The tendency of ENSO will depend on whether El Nino gets established this year end or not.
However, in this forecast we are least bothered about the ENSO
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3) Introduction to the Arctic Oscillation - 

AO- Arctic Oscillation is not much known to the people of India as the parameter is not used for making any forecast ( Long Range/Short Range) relating to India. However, in this study we observed that the AO seems to have some association with the Indian Winters. Before we get into the observational part, lets understand the basics of the AO

AO is an oscillatory phenomena characterised by dipolar natured air pressure across the High Latitudes and the Mid Latitudes simultaneously. AO is  Characterised by two prominent modes-
1) The Positive
2) The Negative

The Positive Mode of the AO is characterised by the formation of low pressure in the Polar Regions and subsequent higher pressure in the Mid latitudes refraining the cool air from the higher latitudes to spread in the mid latitudes. Vice versa conditions are observed during the Negative Mode

(all jet streams mentioned below are the subtropical jet streams)

The most important feature of the AO is that it influences the subtropical jet stream. In the case of the positive AO, the jet streams have a zonal flow from the usual west-east direction. Whereas in the case of the Negative AO, the jet streams don't have a zonal flow rather they have a wave shaped ( comprised of crest and troughs) as seen in the below figure-

In the above figure, one can clearly see how the cold air enters the mid latitudes during the Negative phase.

Arctic Oscillation is given by the Arctic Oscillation Index ( AOI). The AOI is one of the most unpredictable index and one can't predict how the AO will behave as it varies stochastically.

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4) Relation between the Arctic Oscillation and minimum temperatures during winter

Since the volume of investigated data is large, we use the SAMPLING method from statistics.

Hypothesis- 
1) It has been observed from the data that the minimum temperatures in a region stretching southwards from the Maharashtra-Madhya Pradesh have a inverse relation with the AOI
i.e the higher the AOI (MORE POSITIVE), the lower the temperatures during the Winter ( as compared to the previous years).

2) Minimum temperatures in a region stretching northwards from the Maharashtra-Madhya Pradesh border are directly proportional to the AOI 
i.e the lower the AOI ( MORE NEGATIVE IN MAGNITUDE) min temperature VS previous year's temperature. 

3) The geographical boundary at the Maharashtra-Madhya Pradesh region across which the AOI varies directly/inversely is being coined as the Deoras limit. 

 The result prominently applies for the December month so we shall investigate the relation for December month only

*** South of Deoras Limit*** 

Data set for Nagpur,Maharashtra

Average Monthly min temperature (1950-2002)
http://indiawaterportal.org/met_data/

AOI Historical ( 1950-2012)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table


  YEAR        MONTH         AOI           AVG MIN TEMP(C)
   1950            DEC             -1.928           13.028
   1951            DEC              1.987           12.765


   1951            DEC              1.987           12.765
   1952              "                  -1.827          14.991

   1969              "                  -1.856          13.232
   1970              "                   -0.399         11.944

   1994              "                   0.894          13.044
   1995              "                   -2.127         15.403

   1995              "                   -2.127         15.403
   1996              "                   -1.721         13.101


One infers that for a period say 1951 the min avg temp for december was lesser than 1950 when the AOI had opposite relation
Thus through sampling, the probability of the above relation holding good is high though there are some cases where the relation doesn't hold good.

*** NORTH OF DEORAS LIMIT***

For simplicity and to reduce the length of this forecast, we shall consider the case for Ludhiana,Punjab. However from the given links, one can verify that the relation holds good for all the areas North of Deoras Limit

    YEAR        MONTH         AOI           AVG MIN TEMP(C)

     1950            DEC             -1.928              5.457
     1951            DEC              1.987              8.439


     1951            DEC              1.987              8.439
     1952              "                  -1.827             7.523

     1997              "                   -0.071             5.676
     1998              "                   1.353              8.113

     1972              "                    1.238             8.349
     1973              "                    -0.181            5.475


Thus through sampling, the probability of the above relation holding good is high though there are some cases where the relation doesn't hold good.

Though it has not been calculated but we do suspect that when calculated on a 3-4 month basis, the results will come better and the anomalies in the result will decrease considerably. 

Reason- 

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5) Estimated Arctic Oscillation Index during 2012 Winter

As stated above, the AO is a stochastically varying phenomena. September 2012 had AOI of 0.772

Here is the observed and forecasted value of the AOI

Thus from the models, it can be inferred that AOI will remain in the negative mode for remaining half of Oct for sure 

Since its an experimental forecast, I think that the AOI will remain in the negative mode till somewhere Mid November after which it will oscillate between the negative and positive phase.

So the OND average AOI as per my estimate shall be negative considering the happening Oct negative AOI and estimated Nov AOI
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6) The 2012 Winter Forecast

Like said above, it will all depend on the AOI. If the net AOI turns out to be positive then areas South of Deoras Limit will experience slightly cooler than normal winter and vice versa

However considering the expected negative AOI, it appears that Northern Deoras Limit regions will experience a marginal cooler than normal winter whereas areas south of the limit shall experience a slightly warmer winter with the intensity increasing towards South India 

Zone Wise- 

North India- 

1] Jammu and Kashmir,Himachal Pradesh,Uttaranchal

  Normal winter conditions will be observed here.The temperature anomaly ( All season Average) shall be around 0.2C to 0.1c less than average temperature.

2] Punjab,Haryana,Chandigarh,New Delhi

The overall temperature anomaly in these regions depends on the western disturbance. However it does appear that these regions will witness ( 0.5C to 0.7C) less than average temperature. 

After the snowfall events, temperature in the plains will drop suddenly but average will be near to the predicted value.

** We shall not estimate the number of western disturbances as its a debatable topic. However, the precipitation in the hilly areas seems NORMAL

3] Madhya Pradesh,Rajasthan,Uttar Pradesh,Gujarat 

A Cooling effect is likely in these areas as the jet streams coupled with the negative AOI influence shall lead to drop of temperatures due to more cool air incursion. 

** Uttar Pradesh will have NORMAL winter and hence I don't expect any anomaly in the temperature. 

The Average temperatures will be ( ~0.5C) less than average normal temperature. Areas like Rajasthan-Gujarat border can experience lesser than avg temp by a factor of around ( 0.8C to 1C)

4] Northern Chattisgarh,Bihar and Jharkhand,West Bengal
Regions will witness a slightly cooler than normal winter conditions with average variation of about 0.3-0.5C ( lesser than the normal) 

5] Sikkim,NE India 

Though this shall not support the Deoras limit but it appears that the regions will witness warmer conditions with temperatures around ( 0.3 to 0.5C) more than normal 

6) Central,Northern,Eastern Maharashtra,
These areas will be witnessing normal winter conditions but the tendency shall be a slightly warmer than normal by a factor of around 0.3C. 

The expected record min temperature of Nagpur for the season shall be in the range of 7.5C ( +/- 0.5C)

7) Southern Maharashtra and remainder Southern India
Warmer than normal conditions with temperature variation of a factor of around ( 0.5C to 1C) more than Normal for Southern India

* No forecast available for Lakshadweep, Andamaan Nicobar Is.*
----------------------------------------------------------------------------------------------------------------------------------

7) References & Acknowledgements

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/

http://www.apcc21.net/eng/service/fore/lmon/japcc030101_lst.jsp

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml#forecast

http://en.wikipedia.org/wiki/Arctic_oscillation

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_mrf.shtml

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

http://metdweather.blogspot.in/2010/11/2010-winter-forecast-for-india.html

http://metdweather.blogspot.in/2011/10/2011-winter-forecast-of-india.html

http://indiawaterportal.org/met_data/

http://ggweather.com/enso/oni.htm

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.ao.cdas.gif

http://www.apcc21.net/eng/service/fore/lmon/japcc030101_lst.jsp

http://nsidc.org/icelights/2012/02/02/the-arctic-oscillation-winter-storms-and-sea-ice/
http://weather.unisys.com/archive/sst/

2012 WINTER FORECAST FOR INDIA ( PUBLIC VERSION)

(C) 2012 AKSHAY DEORAS

metdweather.blogspot.com

All Rights Reserved.....

FOR MORE DETAILS, REFER TO THE TECHNICAL VERSION OF THE WINTER FORECAST 

From the Desk,

14th Oct 2012

0400hrs IST

Nagpur,India

Dear Readers, 

The Official forecast for the 2012 Winter in India is below.

This year's forecast is an experimental forecast as we have used a new technique for weather forecasting. Till the last year, the winter forecast used to be made using the weather models directly. However there are many errors in it which ultimately spoil the forecast accuracy. This year's winter forecast consists of two parts. One is a technical part having all the scientific background for the forecast whereas the other one is the non technical or the public version for lucid understanding of the people. 

As per the forecast, it appears that Northern half of the country will experience cooler than normal winter whereas southern half will experience warmer than normal conditions. As a result, the net forecast for 2012 Winter in India seems "NORMAL WINTER''

We also expect to cross the 2,00,000 pageviews after the Winter forecasts are published. 

Thanks for the support !

For any feedback/suggestion, you can mail me at metdweather@live.com 

Greetings! 

Akshay Deoras

---------------------------------------------------------------------------------

*It appears that more or less a ENSO Neutral will persists through the Northern Hemisphere winter with a slight El Nino conditions emerging towards the year end.

*** NET AVERAGE IS CONSIDERED, INDIA WILL HAVE A NORMAL WINTER FOR THE SEASON***

Zone Wise- 

North India- 

1] Jammu and Kashmir,Himachal Pradesh,Uttaranchal

  Normal winter conditions will be observed here.The temperature anomaly ( All season Average) shall be around 0.2C to 0.1c less than average temperature.

2] Punjab,Haryana,Chandigarh,New Delhi

The overall temperature anomaly in these regions depends on the western disturbance. However it does appear that these regions will witness ( 0.5C to 0.7C) less than average temperature. 

After the snowfall events, temperature in the plains will drop suddenly but average will be near to the predicted value.

** We shall not estimate the number of western disturbances as its a debatable topic. However, the precipitation in the hilly areas seems NORMAL

3] Madhya Pradesh,Rajasthan,Uttar Pradesh,Gujarat 

A Cooling effect is likely in these areas as the jet streams coupled with the negative AOI influence shall lead to drop of temperatures due to more cool air incursion. 

** Uttar Pradesh will have NORMAL winter and hence I don't expect any anomaly in the temperature. 

The Average temperatures will be ( ~0.5C) less than average normal temperature. Areas like Rajasthan-Gujarat border can experience lesser than avg temp by a factor of around ( 0.8C to 1C)

4] Northern Chattisgarh,Bihar and Jharkhand,West Bengal
Regions will witness a slightly cooler than normal winter conditions with average variation of about 0.3-0.5C ( lesser than the normal) 

5] Sikkim,NE India 

Though this shall not support the Deoras limit but it appears that the regions will witness warmer conditions with temperatures around ( 0.3 to 0.5C) more than normal 

6) Central,Northern,Eastern Maharashtra,

These areas will be witnessing normal winter conditions but the tendency shall be a slightly warmer than normal by a factor of around 0.3C. 

The expected record min temperature of Nagpur for the season shall be in the range of 7.5C ( +/- 0.5C)

7) Southern Maharashtra and remainder Southern India

Warmer than normal conditions with temperature variation of a factor of around ( 0.5C to 1C) more than Normal for Southern India 

* No forecast available for Lakshadweep, Andamaan Nicobar Is.*

Predict the 2012 Winter Contest of METD WEATHER

To enable people's participation in Meteorology and particularly in the Weather of India, METD WEATHER announces a "Special Offer". The contest is named as "Predict the 2012 Winter of India". The contest is a very simple contest and definitely doesn't require any technical brains to answer. The participants also are not expected to be profession/passionate meteorologist or others having knowledge of meteorology. This will enable a common man to participate. 

As was announced, the 2012 Winter Forecast of METD WEATHER will be issued on Sunday,14th Oct 2012 at 1000hrs IST ( 0430hrs GMT). 

But what are the participants expected to do???

Simple, just predict what METD WEATHER's forecast will point at. Simple statistics imply that there are only three equally likely events for the 2012 Winter of India

Either- 

1) The Winter will be colder than normal

2) The Winter will be normal 

3) The Winter will be warmer than normal 

So the participant has to select any one of the option and follow the following procedure to submit their entry. 

What will winners get?? 

The person whose estimate matches with METD WEATHER forecast will get a chance to get featured on the METD WEATHER BLOG and also will get a chance to display his weather related story. Winners will be notified accordingly and will be asked to submit their weather story 

What are the steps to be followed?

Here is the proceedure an interested person must follow for getting involved! 

1) The person needs to comment on the 2012 overall winter for India in one line by mentioning whether he/she thinks that the winter will have ANY ONE OF THE BELOW NATURE-
1) NORMAL
2) WARMER THAN NORMAL
3) COLDER THAN NORMAL

STEP 2- 

After the person is firm with his guess, he needs to send a Facebook message

***

to METD WEATHER. 

The Facebook page of METD WEATHER is facebook.com/deorasakshay 

Those who aren't connected on our Facebook page need to just click the "Like" and then proceed. 

This can be done from any device. The person needs to open the Facebook METD WEATHER pageand click 'Message' option. He/She must comment in one line the option he/she feels from the above three and send it to METD WEATHER

STEP 3-
After you send a message to us, we will reply you thus confirming.

THE LAST DATE FOR THE SUBMISSION IS FRIDAY,12TH OCT 2012 1200hrs GMT. So the comments much reach before this

THE WINNERS WILL THEN BE NOTIFIED ACCORDINGLY AND WILL GET A CHANCE TO GET FEATURED ON THE BLOG WITH THEIR WEATHER STORY..

*** The comments must be messaged to METD WEATHER FACEBOOK. Commenting on the posts and thus submitting will not be considered!!!

So what are you waiting for????????

Regards,

Akshay Deoras

Owner,Severe Weather Forecaster

METD WEATHER

India

metdweather@live.com