Original source: http://tgftp.nws.noaa.gov/data/raw/wt/wtin20.dems..txt, recovered at: 2017-12-07 0315Z

WTIN20 DEMS 070330

SPECIAL TROPICAL WEATHER OUTLOOK

DEMS-RSMC TROPICAL CYCLONES NEW DELHI DATED 07.12.2017
SPECIAL TROPICAL WEATHER OUTLOOK FOR NORTH INDIAN OCEAN
(THE BAY OF BENGAL AND ARABIAN SEA) VALID FOR NEXT 72 HOURS
ISSUED AT 0300 UTC OF 07.12.2017 BASED ON 0000 UTC OF 07.12.2017.
BAY OF BENGAL & ANDAMAN SEA:

DEPRESSION OVER SOUTHEAST BAY OF BENGAL:


THE DEPRESSION OVER SOUTHEAST BAY OF BENGAL &
NEIGHBOURHOOD MOVED LIKELY NORTHWARDS WITH A
SPEED OF ABOUT 20 KMPH DURING PAST 6 HOURS AND
LAY CENTRED AT 0000 UTC OF TODAY, THE 07 DECEMBER,
2017 NEAR LATITUDE 11.1� N AND LONGITUDE 88.0 �E,
ABOUT 930 KM TO THE EAST-SOUTHEAST OF MACHILLIPATNAM
AND 970 KM SOUTH-SOUTHEAST OF GOPALPUR. THE SYSTEM IS
VERY LIKELY TO MOVE NORTH-NORTHWESTWARDS AND REACH
NORTH ANDHRA PRADESH AND SOUTH ODISHA COASTS AROUND
9TH DECEMBER MORNING. THE SYSTEM IS LIKELY TO INTENSIFY
FURTHER INTO A DEEP DEPRESSION DURING NEXT 24 HOURS.
HOWEVER, THERE IS A PROBABILITY OF SLIGHT WEAKENING
OF THE SYSTEM WHEN IT REACHES NEAR NORTH ANDHRA PRADESH
AND SOUTH ODISHA COASTS.

THE ESTIMATED CENTRAL PRESSURE IS ABOUT 1004 HPA AND
THE MAXIMUM SUSTAINED SURFACE WIND SPEED IS 25 KNOTS
GUSTING TO 35 KNOTS. SEA CONDITION IS ROUGH TO VERY
ROUGH AROUND SYSTEM CENTRE. ACCORDING TO THE LATEST
SATELLITE IMAGERY THE INTENSITY IS T1.5. ASSOCIATED
BROKEN LOW TO MEDIUM CLOUDS WITH INTENSE TO VERY INTENSE
CONVECTION LIE OVER SOUTHEAST BAY OF BENGAL AND ADJOINING
CENTRAL BAY, SOUTHWEST BAY AND ANDAMAN SEA. THE MAXIMUM
CLOUD TOP TEMPERATURE IS MINUS 80 0C. SATELLITE IMAGERIE
INDICATES THE CONVECTIVE CLOUDS HAVE ORGANISED DURING
PAST 6 HOURS AND DURING PAST 24 HOURS THE CONVECTIVE
CLOUD OF COSOLIDATIVE. HOWEVER THE MAJORITY OF CONVECTION
IS DISPLACED NORTHWARD FROM LOW LEVEL CIRCULATION CENTER.

THE SEA SURFACE TEMPERATURE OVER THE REGION IS 29-30 0C.
SST IS DECREASING TO THE NORTH AND TO THE WEST. THE
OCEAN THERMAL ENERGY IS ABOUT 100 KJ/CM2 OVER THE
SYSTEM AREA. IT IS DECREASING TO THE NORTH. THE VERTICAL
WIND SHEAR IS LOW TO MODERATE AROUND THE SYSTEM CENTER
AND IT IS INCREASING TO NORTH AND TO THE WEST. THE LOW
LEVEL RELATIVE VORTICITY IS AROUND 100 X 10 -6 S-1 TO
THE SOUTHEAST OF THE SYSTEM CENTRE. LOW LEVEL CONVERGENCE
IS AROUND 20 X 10 -5 S-1 TO THE NORTHWEST OF THE SYSTEM
CENTRE. UPPER LEVEL DIVERGENCE IS ABOUT 40 X 10 -5 S-1
TO THE NORTHWEST OF THE SYSTEM CENTER. MADDEN JULIAN
OSCILLATION (MJO) LIES IN PHASE 5 WITH AMPLITUDE MORE
THAN 1 AND IS LIKELY TO MOVE TO PHASE 6 IN NEXT TWO DAYS.

EVENTHOUGH THE SYSTEM PRESENTLY LIES OVER FAVOUABLE
OCEAN THERMAL CONDITIIONS, IT IS EMBEDED IN A HIGH
WIND SHEAR REGIME. HENCE, THE SYSTEM IS NOT EXPECTED
TO INTENSIFY RAPIDLY AND ITS INTENSIFICATION WILL BE
LIIMITED UPTO DEEP DEPRESSION. FURTHER, WHEN THE SYSTEM
REACHES NEAR TO THE COAST IT WILL ENCOUNTER COLDER SEA,
LOWER OCEAN THERMAL ENERGY AND INCREASED SHEAR DUE TO
THE STRONG UPPER LEVEL WINDS IN ASSOCIATION WITH A DEEP
TROUGH IN WESTERLIES. AS A RESULT THERE IS POSSIBILITY
OF WEAKENING OF THE SYSTEM WHEN IT REACHES NEAR THE COAST.
UNDER THE INFLUNCE OF ANTI CYCLONIC CIRCULATION OVER
EASTCENTRAL BAY OF BVENGAL, THE NORTHWESTERLY TO
NORTH-NORTHWESTERLY WINDS PREVAIL OVER THE SYSTEM
AT UPPER LEVEL, WHICH SUGGEST THE NORTH-NORTHWESTWARD
MOVEMENT OF THE SYSTEM AND DEEP LAYER MEAN ALSO SUGGEST
THE NORTH-NORTHWESTWARD MOVEMENT OF THE SYSTEM. ALL THE
NWP MODELS ARE IN AGREEMENT WITH THE ABOVE CONCLUSIONS.