[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031157
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT OCT 03 2015

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...

HURRICANE JOAQUIN IS CENTERED NEAR 25.6N 72.5W AT 03/1200 UTC OR
ABOUT 140 NM NE OF SAN SALVADOR BAHAMAS AND ABOUT 570 NM SW OF
BERMUDA MOVING NE AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 940 MB. MAXIMUM SUSTAINED WIND SPEED IS 110 KT WITH GUSTS TO
135 KT. NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION IS FROM
22N TO 27N BETWEEN 70W AND 75W. SCATTERED MODERATE CONVECTION
AND TSTMS ARE FROM 21N TO 27N BETWEEN 69W AND 76W AND FROM 17N
TO 29N BETWEEN 60W AND 69W. THE OUTER RAINBANDS OF JOAQUIN
REACHES THE NORTH-CENTRAL AND AND NE CARIBBEAN WHERE SCATTERED
SHOWERS AND TSTMS ARE NOTED...INCLUDING EASTERN CUBA...WINDWARD
PASSAGE...HISPANIOLA...PUERTO RICO AND THE LEEWARD ISLANDS. SEE
LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

A 1005 MB NON-TROPICAL LOW IS CENTERED NEAR 26N52W OR ABOUT 740
NM ESE OF BERMUDA PRODUCING GALE-FORCE WINDS N OF THE CENTER.
SHOWERS AND TSTMS ASSOCIATED WITH THIS LOW GREATLY DIMINISHED
DURING THE LAST COUPLE OF HOURS AND MERGED WITH CONVECTION
ASSOCIATED WITH A FRONTAL BOUNDARY JUST E OF IT.
SCATTERED/ISOLATED SHOWERS AND TSTMS ARE WITHIN 140 NM OF THE
LOW CENTER. EVEN THOUGH ENVIRONMENTAL CONDITIONS ARE FORECAST TO
BE CONDUCIVE FOR THE LOW TO ACQUIRE MORE TROPICAL
CHARACTERISTICS FOR ANOTHER DAY...DEVELOPMENT IS EXPECTED TO BE
HINDERED BY STRONG UPPER-LEVEL WINDS ASSOCIATED WITH HURRICANE
JOAQUIN. GALE WINDS ARE EXPECTED TO DIMINISH LATER TODAY. A
MEDIUM CHANCE EXISTS FOR THE LOW TO DEVELOP INTO A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...

A TROPICAL WAVE CAME OFF THE AFRICAN COAST FRIDAY MORNING AND NOW
IS MOVING OVER THE CAPE VERDE ISLANDS WITH AXIS APPROXIMATELY
ALONG 24W. THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT
AT THE LOWER LEVELS THAT ENHANCES SCATTERED SHOWERS FROM 03N TO
09N BETWEEN 21W AND 28W. CONVECTION IN THE NORTHERN WAVE
ENVIRONMENT IS BEING INHIBITED BY THE PRESENCE OF DRY AIR AND
DUST AS INDICATED BY METEOSAT ENHANCED IMAGERY. MODEL GUIDANCE
INDICATE THIS WAVE WILL MERGE WITH THE TROPICAL WAVE AHEAD OF IT
WITHIN THE NEXT 24 HOURS.

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH TILTED AXIS
EXTENDING FROM 16N34W TO A 1009 MB LOW NEAR 09N30W...MOVING W AT
5-10 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS
EMBEDDED IN A MODERATE TO HIGH MOIST ENVIRONMENT FROM THE
SURFACE TO NEARLY 700 MB THAT ALONG WITH MIDDLE TO UPPER LEVEL
DIFFLUENCE IN THE WAVE REGION SUPPORT SCATTERED MODERATE
CONVECTION AND TSTMS FROM 03N TO 13N BETWEEN 29W AND 37W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF WEST AFRICA NEAR
11N15W TO 08N22W TO A 1009 MB LOW NEAR 09N30W TO 09N37W. FOR
CONVECTION INFORMATION REFER TO THE TROPICAL WAVES SECTION.

...DISCUSSION...

GULF OF MEXICO...

BROAD SURFACE LOW PRESSURE ASSOCIATED WITH HURRICANE JOAQUIN IN
THE SW N ATLC COVERS THE BASIN AND PROVIDE N-NW WIND FLOW OF 15-
20 KT ACROSS THE GULF...THE STRONGEST WINDS BEING IN THE
NORTHERN GULF DUE TO A TIGHT PRESSURE GRADIENT WITH A BROAD
RIDGE COVERING THE CENTRAL AND NE U.S. WITH THE PASSAGE OF A
COLD FRONT THESE LAST TWO DAYS...DRY STABLE LOW-LEVEL AIR COVERS
THE BASIN WHILE WATER VAPOR IMAGERY CONTINUE TO SHOW VERY DRY
AIR ALOFT...THUS SUPPORTING FAIR WEATHER CONDITIONS AND CLEAR
SKIES. LOW PRESSURE AND SIMILAR WEATHER CONDITIONS WILL PREVAIL
THE NEXT THREE DAYS WHILE JOAQUIN TAKES A NNE TRACK IN THE ATLC.
WINDS ARE EXPECTED TO BECOME LESS THAN 15 KT BY MONDAY.

CARIBBEAN SEA...

THE OUTER RAINBANDS OF MAJOR HURRICANE JOAQUIN OVER THE SW N
ATLC CONTINUE TO AFFECT THE NORTH-CENTRAL AND THE NE CARIBBEAN
WHERE SCATTERED SHOWERS AND TSTMS ARE NOTED...INCLUDING EASTERN
CUBA...WINDWARD PASSAGE...HISPANIOLA...PUERTO RICO AND THE
LEEWARD ISLANDS. IN TERMS OF WIND...SW TO W WINDS OF 20 TO 25 KT
ARE N OF 18N BETWEEN 73W AND 78W...INCLUDING THE WINDWARD
PASSAGE WITH SEAS TO 8 FT IN THE WINDWARD PASSAGE. W-NW WIND
FLOW OF 15 KT IS OVER THE NW CARIBBEAN WHILE S-SE WIND FLOW OF
SIMILAR MAGNITUDE COVERS THE EASTERN BASIN. A SURFACE TROUGH IS
OVER THE NW CARIBBEAN WATERS FROM 21N78W SW TO COASTAL WATERS OF
HONDURAS NEAR 16N87W ENHANCING SCATTERED SHOWERS AND TSTMS
WITHIN 120 NM EITHER SIDE OF THE TROUGH. SHALLOW MOISTURE OVER
THE S AND SE CARIBBEAN ALONG WITH DIFFLUENCE ALOFT SUPPORT
ISOLATED SHOWERS. LOOKING AHEAD...AREAS OF CONVECTIVE
PRECIPITATION ARE EXPECTED TO CONTINUE IMPACTING THE NORTHERN
CARIBBEAN THROUGH TONIGHT AS JOAQUIN TRACKS NORTHWARD. SURFACE
WINDS ARE EXPECTED TO DIMINISH BY EARLY SUNDAY.

...HISPANIOLA...

CURRENTLY...THE OUTER CONVECTIVE BANDS OF HURRICANE JOAQUIN IN
THE SW N ATLC ARE PRODUCING SCATTERED TO ISOLATED SHOWERS OVER
HISPANIOLA. IN TERMS OF WIND...SW TO W WINDS OF 20 TO 25 KT ARE
N OF 18N BETWEEN 73W AND 78W...INCLUDING THE WINDWARD PASSAGE
WITH SEAS TO 8 FT IN THE WINDWARD PASSAGE. RAINSHOWERS ARE
EXPECTED TO CONTINUE IMPACTING THE ISLAND THROUGH TONIGHT AS
JOAQUIN TRACKS NORTHWARD. SURFACE WINDS ARE EXPECTED TO DIMINISH
BY EARLY SUNDAY.

ATLANTIC OCEAN...

THE MAIN FEATURE ACROSS THE ATLANTIC IS MAJOR HURRICANE JOAQUIN
OVER THE SW N ATLC. PLEASE REFER TO THE SPECIAL FEATURES SECTION
ABOVE FOR MORE DETAILS. THE SECOND AREA OF INTEREST IS A 1005 MB
NON-TROPICAL LOW CENTERED NEAR 26N52W OR ABOUT 738 NM ESE OF
BERMUDA THAT IS PRODUCING GALE-FORCE WINDS N OF IT.
SCATTERED/ISOLATED SHOWERS AND TSTMS ARE WITHIN 140 NM OF THE
LOW CENTER. A MEDIUM CHANCE EXISTS FOR THE LOW TO DEVELOP INTO A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS. SEE SPECIAL FEATURES
SECTION ABOVE FOR FURTHER INFORMATION. NW OF JOAQUIN...THE TAIL
OF A STATIONARY FRONT IS ANALYZED FROM 30N79W TO 28N79W THAT
ENHANCES SHOWERS AND TSTMS WITHIN 45 NM E OF IT. OVER PORTIONS
OF THE NE AND CENTRAL ATLC...A COLD FRONT EXTENDS FROM 30N25W TO
25N37W TO 25N44W WHERE IT TRANSITIONS TO A STATIONARY FRONT TO
27N48W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE
WITHIN 120 NM S OF THE FRONTAL BOUNDARY. A WEAK SURFACE RIDGE
PREVAILS FARTHER E IN THE NE ATLANTIC.

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

$$
NR
This weather bulletin was brought to you by:
www.nashvilleweather.net