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Cakxky dh [kkM+h esa m".kdfVca/kh; rwQkuksa ds ekxZ vkSj mudh rhozrk ds iwokZuqeku rduhd esa lq/kkj ykus ds fy, iwokZuqeku fun’kZu ifj;kstuk ¼,Q-Mh-ih-½ uked ,d dk;ZØe rS;kj fd;k x;k gSA ,Q-Mh-ih- dk;ZØe dk mÌs’;] ftu {ks=ksa ls vk¡dM+s vO;ofLFkr :i ls izkIr gksrs gSa ogk¡ muds loaf/kZr izs{k.kksa ds lkFk gh lkFk mRrjh fgUn egklkxj esa pØokrksa ds mRiUu gksus] muds rhoz gksus vkSj mudh xfr dk vkdyu djus ds fy, fofHkUu l[;kRed ekSle iwokZuqeku ¼,u- MCY;w- ih-½ fun’kksZ dh {kerk dk izn’kZu djuk rFkk fo’ks"k :i ls caxky dh [kkM+h ls lacaf/kr ogha mlh LFkku ij fy, x, ekiksa ds vk/kkj ij fun’kksZ esa lq/kkj djuk gSA ,Q-Mh-ih- dk;ZØe rhu pj.kksa esa fu/kkfjr fd;k x;k gS uker% ¼i½ izh&ikbyV pj.k ¼15 vDrwcj ls 30 uoacj 2008] 2009½] ¼ii½ ikbyV pj.k ¼15 vDrwcj ls 30 uoacj 2010&2012½ rFkk ¼iii½ vafre pj.k ¼15 vDrwcj ls 30 uoacj 2013&2014½A Hkkjr] fdjk, ds gokbZ tgkt vkSj MªkWilkSansa iz;ksxksa ls 15 vDrwcj ls 30 uoacj 2013&2014 ds nkSjku caxky dh [kkM+h esa cuus okys pØokrksa dk gokbZ tgkt ds tfj, irk yxkus dh ;kstuk cuk jgk gSA bl mÌs’; ds iwfrZ ds fy, ¼i½ izs{k.kkRed mUu;u ¼ii½ pØokr fo’ys"k.k vkSj iwokZuqeku iz.kkyh dk vk/kqfudhdj.k ¼iii½ pØokr fo’ys"k.k vkSj iwokZuqeku izfØ;k ¼iv½ psrkouh mRiknksa dks rS;kj djuk] mudk izLrqrhdj.k rFkk izlj.k ¼v½ fo’oluh;rk mik; vkSj {kerk fuekZ.k ij izkFkfedrk ds vk/kkj ij dk;Z fd, x,A pØokr ds izs{k.k] fo’ys"k.k vkSj iwokZuqeku esa lq/kkj ykus ds fy, fofHkUu dk;Z iz.kkfy;k¡ viukbZ xbZaA o"kZ 2008&11 ds nkSjku ,Q-Mh-ih- vfHk;ku ds izh&ikbyV vkSj ikbyV pj.kksa esa la;qDr izs{k.kkRed] lapkjkRed vkSj ,u-MCY;w-ih- xfrfof/k;ksa esa vusd jk"Vªh; laLFkkuksa us Hkkx fy;kA ,Q-Mh-ih- ds igys vkSj mlds ckn dh izs{k.kkRed iz.kkfy;ksa dh rqyuk ls {ks= esa jsMkj] Lopkfyr ekSle dsUnz ¼,- MCY;w-,l-½] mPp iou xfr fjdkWMjksa esa egRoiw.kZ lq/kkj dk irk pyk gSA bl lq/kkj ls ekWuhVju vkSj iwokZuqeku esa gksus okyh =qfV;ksa esa deh vkbZ gSA th- ,Q- ,l- MCY;w vkj- ,Q] ,p- MCY;w- vkj- ,Q- vkSj vlsEcy iwokZuqeku iz.kkyh ¼bZ- ih- ,l-½ ds vkjaHk gksus ls ,u- MCY;w- ih- funsZ’kksa ds dk;Z fu"iknu esa o`f) gqbZ gSA bl 'kks/k i= esa bl ifj;kstuk dh miyfC/k;ksa ds egRoiw.kZ y{k.kksa lfgr leL;kvksa vkSj laHkkoukvksa dks izLrqr fd;k x;k gS rFkk mudh foospuk dh xbZ gSA pØokrksa dk gokbZ tgkt }kjk irk yxkus ds fy, ckj&ckj fd, x, iz;klksa ds ckotwn ;g dk;Z vHkh laHko ugha gks ldk gSA o"kZ 2013&14 ds nkSjku Hkkoh vfHk;ku ds le; ;g ,d eq[; pqukSrh gksxhA A programme has been evolved for improvement in prediction of track and intensity of tropical cyclones over the Bay of Bengal resulting in the Forecast Demonstration Project (FDP). FDP programme is aimed to demonstrate the ability of various Numerical Weather Prediction (NWP) models to assess the genesis, intensification and movement of cyclones over the north Indian ocean with enhanced observations over the data sparse region and to incorporate modification into the models which could be specific to the Bay of Bengal based on the in-situ measurements. FDP Programme is scheduled in three phases, viz., (i) Pre-pilot phase (15 Oct - 30 Nov 2008, 2009, (ii) Pilot phase (15 Oct - 30 Nov, 2010-2012) and (iii) Final phase (15 Oct - 30 Nov, 2013-14). India is planning to take up aircraft probing of cyclones over the Bay of Bengal during 15 Oct - 30 Nov, 2013-14 with hired aircraft and dropsonde experiments. To accomplish the above objective, the initiative was carried out with priorities on (i) observational upgradation, (ii) modernisation of cyclone analysis and prediction system, (iii) cyclone analysis and forecasting procedure, (iv) warning products generation, presentation & dissemination, (v) confidence building measures and capacity building. Various strategies were adopted for improvement of observation, analysis and prediction of cyclone. Several national institutions participated for joint observational, communicational & NWP activities during the pre-pilot and pilot phases of FDP campaign during 2008-11. The comparison of observational systems before and after FDP indicates a significant improvement in terms of Radar, Automatic Weather Station (AWS), high wind speed recorders over the region. It has resulted in reduction in monitoring and forecasting errors. The performance of NWP models have increased along with the introduction of NWP platforms like IMD GFS, WRF, HWRF and ensemble prediction system (EPS). Salient features of achievements along with the problems and prospects of this project are presented and discussed in this paper. With repeated attempts, the aircraft probing of cyclones could not be possible till now. It is a major challenge for the future campaign during 2013-14.

In this paper an attempt has been made to investigate different stability indices in relation to the occurrence of thunderstorms in order to determine the critical values of these indices for Delhi (28.35° N / 77.12° E) using pre monsoon data for the years 1999 - 2004. The study shows that the critical values of Showalter Index (SI), Lifted Index (LI), K Index (KI), Total Totals Index (TTI), and Sweat Index (SWI) are respectively < 2 °C, < 0 °C, > 24 °C, > 44.5 °C and > 100 for the thunderstorm to occur over Delhi. The corresponding common critical ranges of Lifted Condensation Level (LCL), Level of Free Convection (LFC), Equilibrium Level (EL) and Precipitable Water (PW) are respectively 923 hPa – 695 hPa, 856 hPa – 504 hPa, 545 hPa – 109 hPa and 18 mm – 54 mm. Testing of critical values of indices and the corresponding common critical ranges of LCL, LFC, EL and PW during pre-monsoon seasons of the years 2005 and 2006 shows that they are matching well with the respective critical values/ranges in most of the thunderstorm days.

In this study an attempt has been made to develop climatology of thunderstorm, hail and squall over the northeast and adjoining east India region based on data of 26 India Meteorological Department (IMD) observatories for the months of April and May during 1981-2008. The data of 8 Indian Air Force (IAF) observatories in these regions which are available for the period of 1991-2008 have also been considered. The interannual & intraseasonal variation, climate change aspects and diurnal variation of occurrence of thunderstorms have been analysed and discussed. The frequency and time of occurrence of thunderstorm, hail and squall days over the region show large spatial variation. The orographically dominant regions as well as the coastal areas are more prone for such activity. There is increasing trend in number of thunderstorm days over some parts of south coastal Orissa and coastal West Bengal and decreasing trend over some parts of north coastal Orissa, Manipur, Mizoram and Tripura in recent years.

The Central Observatory of India Meteorological Department (IMD) at Palace Road, Bangalore reported a record highest monthly rainfall of 604 mm during October, 2005. It was the highest ever monthly rainfall recorded over Bangalore city. However, the surrounding stations in Bangalore district recorded less rainfall. To find out the physical processes leading to this rainfall, the characteristics of rainfall over different stations in Bangalore urban and rural districts during October, 2005 and associated synoptic and thermodynamic features during the month are analysed. The Urban Heat Island (UHI) effect and role of pollution parameters and their relationship with this rainfall have also been analysed. This study can be utilized in better understanding of the impact of urbanization and pollution on rainfall, especially heavy rainfall. It can also help in predicting the heavy rainfall events over the urban centres. The study endorses the earlier finding that the UHI effect leads to moisture convergence and pollutants may work as hygroscopic nuclei over the region to enhance rainfall near the urban centre.

India Meteorological Department (IMD) issues heavy rainfall warning for a meteorological sub-division when the expected 24 hours rainfall over any rain gauge station in that sub-division is likely to be 64.5 mm or more. Though these warnings have been provided since the inception of IMD, a few attempts have been made for quantitative evaluation of these warnings. Hence, a study is undertaken to verify the heavy rainfall warnings over 36 meteorological sub-divisions of India during monsoon months (June-September) and season as a whole. For this purpose, data of recent 5 years (2002-2006) has been taken into consideration. In this connection, the day when heavy rainfall is recorded over at least one station in a sub-division, has been considered as a heavy rainfall day for that sub-division. There is a large spatial and temporal variability in skill scores of heavy rainfall warnings over India during summer monsoon season. Considering the monsoon season as a whole, the Heidke Skill Score (HSS) is relatively less ( 0.50) over Konkan & Goa, Madhya Maharashtra and Gujarat region. There has been improvement in the forecast skill with gradual increase in the critical success index and Heidke skill score over the years mainly due to the Numerical Weather Prediction (NWP) models' guidance available to the forecasters. However, the false alarm rate and missing rate are still very high (> 0.50), especially over many sub-divisions of northwest India, southeast peninsula and NMMT.

The 26th July 2005 exceptionally heavy rainfall event over Mumbai has been mainly attributed to a mesoscale low/vortex off Konkan coast and urban heat island (UHI) effect as demonstrated by various research groups. However, these studies are limited on observational evidence regarding the existence of the mesoscale vortex and UHI prior to and during this heavy rainfall event. Hence, a study has been undertaken to examine the existence of the mesoscale low off Konkan coast, which might have triggered this exceptionally heavy rainfall over Mumbai and the possible role of UHI effect over Mumbai on this heavy rainfall event. For this purpose the additional synoptic data from Mumbai high region and daily maximum and minimum temperatures over Mumbai region have been analysed. The analysis confirms the existence of a mesoscale low pressure area and isallobaric low to the west of Dahanu during 25th - 26th July 2005. The analysis of daily maximum and minimum temperatures over Mumbai region confirms the UHI effect during 25th -26th July, 2005.

lkj & Å".kdfVca/kh; pØokr fouk’kdkjh izkÑfrd vkink gksrs gSaA buls tku eky dh cM+h gkfu gksrh gSA pØokr ds /kjkry ls Vdjkus ds ckn eq[; fouk’k mldh izpaM iouksa rFkk rwQkuh ty rjaxksa ls gksrk gSA pØokr ds /kjkry ls Vdjkus ds lgh LFkku dk iwokZuqeku djuk iwokZuqekudrkZvksa rFkk ,tsfUl;ksa] tks lqj{kk ds mik;ksa vFkok iquokZl dk;ksZa esa yxs gSa] ds fy, vR;ar egRoiw.kZ gksrk gSA bl ’kks/k Ik= esa pØokr ds /kjkry ls Vdjkus ds LFkku rFkk le; dk iwokZuqeku djus dk iz;kl fd;k x;k gSA O;fDrxr daI;wVj ij vk/kkfjr ekxZ iwokZuqeku ekWMy Hkkjr ekSle foKku foHkkx ds fofHkUu iwokZuqeku dk;kZy;ksa esas mi;ksx esa gSA izpfyr ekWMy ds fy, nzks.kh ds pØokr ekxZ dh tyok;q rFkk pØokrksa ds iwoZ dh fLFkfr dh tkudkjh dh vko’;drk gksrh gSA lkekU;r;% pØokr ds /kjkry ls Vdjkus ds 24 ls 36 ?kaVs iwoZ rV ds fdukjs dk ok;qnkc de gks tkrk gSA bl v/;;u esa ekxZ iwokZuqeku ds fy, bl izkpy dk leku egRo ds vU; nks izkpyksa ds la;kstu ds lkFk vFkkZr~ 1@3 ¼LFkkf;Ro + tyok;q + nkc ifjorZu½ mi;ksx fd;k x;k gSA blds ifj.kke dsoy tyok;q ,oa LFkkf;Ro ¼DykbesV ,.M ijflLVsaV½ ds mi;ksx ls izkIr fd, x, ifj.kkeksa dh rqyuk esa T;knk lgh gSaA ;fn pØokr ds /kjkry ls Vdjkus ds 12 ls 24 ?kaVs ds vanj dh mldh izfØ;k ij fopkj fd;k tk; rks 24 ?kaVs ds vanj dk nkc ifjorZu] tyok;q ,oa LFkkf;Ro dh rqyuk esa vf/kd egRoiw.kZ gks tkrk gS rFkk /kjkry ls Vdjkus ds 12 ?kaVs iwoZ dk ?kaVkokj nkc ifjorZu pØokr ds /kjkry ls Vdjkus ds lgh LFkku dk irk yxkus esa enn djrk gSA Tropical cyclones are deadly natural disasters. They came large loss of lives and properties. After the landfall, the main damages from cyclones are due to strong winds and storm surges. The forecast of landfall point is most important to forecasters as well as the agencies who are engaged to take safety measures or rehabilitation works. In this paper an attempt has been made to forecast point and time of landfall. Personnel computer based, track forecast models are already in use, in India Meteorological Department’s (IMD) different forecasting offices. The existing model requires cyclone track climatology of the basin and past positions of cyclones. Generally pressure falls along the coast, 24 to 36 hours in advance of cyclone’s landfall. This parameter, in combination with other two, with equal weightage i.e., 1/3 (Persistence + Climatology + Pressure change) have been used for track forecasting in this study. Results are comparatively superior to the results obtained only by using climatology and persistence. When the system is within 12 to 24 hour prior to landfall, the 24 hour pressure change becomes more important than Climatology and Persistence and 12 hour prior landfall the hourly pressure change helps in pinpointing the landfall point.

Severe tropical cyclones are responsible for large casualties and considerable damage to property and agricultural crop. After the landfall, the main damages from cyclones are due to strong wind. An attempt has been made in this paper to study the nature of decay of wind speed of tropical cyclones after landfall for the period 1990-2003. It is found that the maximum wind speed decreased exponentially after landfall. A severe cyclonic storm decay to cyclonic storm within 6 to 9 hours after landfall where as very severe cyclonic storm decay to severe cyclonic storm within 6 hours and to cyclonic storm within 15 hours after the landfall. The mean decay rate is found to be 0.46 for the first 6 hours and 0.59 for the subsequent 6 hours.