[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU NOV 21 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM MELISSA AT 21/0300 UTC IS NEAR
38.1N 42.1W...ABOUT 1320 KM/715 NM...TO THE WEST OF THE AZORES.
MELISSA IS MOVING EAST-NORTHEASTWARD 26 KNOTS. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 984 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 45 KNOTS WITH GUSTS TO 55 KNOTS. PUBLIC ADVISORIES ON
TROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT34 KNHC
AND UNDER AWIPS HEADER MIATCPAT4. FORECAST/ADVISORIES ON
TROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT24 KNHC
AND UNDER AWIPS HEADER MIATCMAT4. GALE-FORCE WINDS ARE EXPECTED
TO AFFECT THE WESTERN AND CENTRAL AZORES BEGINNING LATE
THURSDAY. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 34N
TO 36N BETWEEN 49W AND 51W. WIDELY SCATTERED MODERATE TO
ISOLATED STRONG FROM 31N TO 34N BETWEEN 47W AND 51W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT1/FZNT01 KWBC...FOR
MORE DETAILS ABOUT THE WINDS AND SEA HEIGHTS THAT ACCOMPANY
TROPICAL STORM MELISSA.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH CONTINUES IN THE ATLANTIC
OCEAN TO THE SOUTH OF THE AREA OF TROPICAL STORM MELISSA. BROKEN
TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE
WITHIN 180 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH
32N34W 25N41W 17N49W 9N57W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES ACROSS COASTAL GUINEA NEAR 8N13W TO
5N19W. THE ITCZ CONTINUES FROM 5N19W TO 5N27W 6N31W 5N37W 6N44W.
A SURFACE TROUGH IS ALONG 5N44W 10N48W. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 2N TO 7N
BETWEEN 22W AND 44W. SCATTERED MODERATE TO ISOLATED STRONG FROM
2N TO 8N TO THE EAST OF 22W...AND FROM 4N TO 10N BETWEEN 44W AND
52W.

...DISCUSSION...

THE GULF OF MEXICO...

MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE
GULF OF MEXICO.

A MIDDLE LEVEL TO UPPER LEVEL CENTRAL ATLANTIC/EAST CENTRAL
ATLANTIC OCEAN TROUGH SUPPORTS A COLD FRONT THAT CUTS THROUGH
THE CENTRAL ATLANTIC OCEAN...FROM 32N53W TO 28N65W. THE FRONT
BECOMES STATIONARY FROM 28N65W ACROSS THE NORTHERN BAHAMAS...
SOUTH FLORIDA...INTO THE SOUTHEASTERN GULF OF MEXICO. CONVECTIVE
PRECIPITATION...BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
ISOLATED MODERATE ARE IN THE ATLANTIC OCEAN TO THE NORTH OF
25N80W 27N70W 28N60W 30N50W BEYOND 32N48W...AND IN THE GULF OF
MEXICO TO THE NORTH OF 25N80W 23N86W 25N93W 26N96W.

A SURFACE RIDGE PASSES THROUGH LOUISIANA INTO CENTRAL TEXAS.

...HISPANIOLA...

LARGE SWELLS FROM SUBTROPICAL STORM MELISSA WILL CONTINUE TO
AFFECT HISPANIOLA...PUERTO RICO...SECTIONS OF THE NORTHERN
LEEWARD ISLANDS...AND THE SOUTHEASTERN BAHAMAS DURING THE NEXT
COUPLE OF DAYS...CAUSING LIFE-THREATENING SURF AND RIP CURRENTS.
PLEASE REFER TO STATEMENTS FROM YOUR LOCAL WEATHER SERVICE
OFFICE FOR MORE DETAILS.

A SURFACE TROUGH IS ALONG 19N73W IN THE WESTERN SECTIONS OF
HAITI...ACROSS SOUTHWESTERN HAITI...TO 17N75W AND TO 15N77W.
CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 13N TO 20N
BETWEEN 70W AND 80W.

MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW IS MOVING
ACROSS HISPANIOLA. THIS WIND FLOW IS RELATED TO THE CYCLONIC
WIND FLOW THAT IS MOVING AROUND THE TROUGH THAT IS PART OF
SUBTROPICAL STORM MELISSA. COMPARATIVELY DRIER AIR...APPARENT IN
WATER VAPOR SATELLITE IMAGERY...ALSO COVERS HISPANIOLA.
SCATTERED TO BROKEN LOW LEVEL AND MIDDLE LEVEL CLOUDS AND
POSSIBLE RAINSHOWERS COVER HISPANIOLA.

THE GFS FORECAST FOR 250 MB SHOWS THAT NORTHWESTERLY WIND FLOW
WILL PASS ON TOP OF HISPANIOLA DURING THE NEXT 48 HOURS. A
TROUGH WILL CUT ACROSS THE NORTHEASTERN CORNER OF THE CARIBBEAN
SEA TOWARD THE NETHERLANDS ANTILLES FOR THE ENTIRE TIME. THE GFS
FORECAST FOR 500 MB SHOWS THAT NORTHERLY WIND FLOW WILL PASS ON
TOP OF HISPANIOLA FOR THE NEXT 48 HOURS. AN ANTICYCLONIC
CIRCULATION CENTER WILL BE IN THE NORTHWESTERN CORNER OF THE
CARIBBEAN SEA FOR THE ENTIRE TIME. THE GFS FORECAST FOR 700 MB
SHOWS THAT HISPANIOLA WILL START WITH WEAK TO SLIGHTLY
ANTICYCLONIC WIND FLOW FOR THE FIRST 12 TO 18 HOURS. CYCLONIC
WIND FLOW WITH AN INVERTED TROUGH WILL COVER THE AREA FOR MOST
OF THE REST OF THE FORECAST PERIOD...UNTIL THE LAST 6 HOURS OR
SO WHEN ANTICYCLONIC WIND FLOW RETURNS.

THE REST OF THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE
CARIBBEAN SEA TO THE EAST OF 74W. HIGHER LEVEL ANTICYCLONIC WIND
FLOW IS MOVING ACROSS THE TOP OF THE SAME AREA. MIDDLE LEVEL TO
UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA TO THE WEST
OF 74W. A WEAK MIDDLE LEVEL TO UPPER LEVEL TROUGH CUTS ACROSS
CENTRAL SECTIONS OF HISPANIOLA.

THE MONSOON TROUGH PASSES THROUGH 8N75W IN COLOMBIA...TO 8N81W
IN PANAMA...BEYOND 9N85W IN SOUTHERN COSTA RICA...INTO THE
EASTERN PACIFIC OCEAN. NO SIGNIFICANT DEEP CONVECTIVE
PRECIPITATION IS APPARENT IN SATELLITE IMAGERY.

THE REST OF THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 15N23W JUST TO THE EAST OF THE CAPE VERDE ISLANDS. CYCLONIC
WIND FLOW COVERS THE AREA FROM 3N TO 24N BETWEEN AFRICA AND 40W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT1/FZNT01 KWBC...FOR
MORE DETAILS ABOUT THE WINDS AND SEA HEIGHTS THAT ACCOMPANY
TROPICAL STORM MELISSA. ONE AREA OF INTEREST CONSISTS OF
SOUTHWEST TO WEST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS 9 TO 13
FEET TO THE NORTH OF 29N BETWEEN 37W AND 44W. A SECOND AREA OF
INTEREST CONSISTS OF WINDS 20 KNOTS OR LESS AND SEA HEIGHTS 8 TO
12 FEET ELSEWHERE TO THE NORTH OF 25N BETWEEN 37W AND 53W. A
THIRD AREA OF INTEREST CONSISTS OF WINDS 20 KNOTS OR LESS AND
SEA HEIGHTS TO 8 FEET TO THE SOUTH OF 24N BETWEEN 65W AND 72W. A
FOURTH AREA OF INTEREST CONSISTS OF A COLD FRONT 31N56W
28N65W...THE STATIONARY TO 26N80W EXPECT NORTHEAST WINDS 20 TO
25 KNOTS AND SEA HEIGHTS 8 TO 10 FEET. A FIFTH AREA OF INTEREST
CONSISTS OF WINDS 20 KNOTS OF LESS AND SEA HEIGHTS TO 9 FEET. A
SIXTH AREA OF INTEREST CONSISTS OF THE AREA THAT IS TO THE EAST
OF 20N41W 10N47W 7N42W. EXPECT WINDS 20 KNOTS OR LESS AND SEA
HEIGHTS

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
MT


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