[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUN 21 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

HURRICANE CHRIS IS CENTERED NEAR 41.1N 43.2W AT 21/1500 UTC OR
ABOUT 540 NM SE OF CAPE RACE NEWFOUNDLAND MOVING NE AT 17 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB. MAXIMUM SUSTAINED
WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SCATTERED MODERATE
CONVECTION IS FROM 40N-43N BETWEEN 42W-46W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC
FOR MORE DETAILS.

SOUTHWESTERLY UPPER LEVEL DIFFLUENT FLOW IS OVER MUCH OF THE
GULF OF MEXICO THIS AFTERNOON BETWEEN AN UPPER LEVEL LOW
CENTERED OVER NORTHERN MEXICO NEAR 27N100W AND AN UPPER LEVEL
RIDGE TO THE SOUTHEAST WITH AXIS FROM SOUTHERN MEXICO NEAR
17N97W TO OVER THE SOUTHERN FLORIDA PENINSULA NEAR 26N81W. WHILE
A MIDDLE TO UPPER LEVEL DIFFLUENT ENVIRONMENT REMAINS IN PLACE
AND CONTINUES TO BECOME MORE FAVORABLE FOR TROPICAL CYCLONE
DEVELOPMENT...AT THE SURFACE...A BROAD SURFACE TROUGH IS
ANALYZED FROM THE NE GULF NEAR 29N84W INTO A WEAK 1008 MB LOW
CENTERED NEAR 21N90W ON THE NORTHWESTERN TIP OF THE YUCATAN
PENINSULA. MOST OF THE SIGNIFICANT DEEP CONVECTION WITH THIS
SYSTEM IS LOCATED TO THE SE OF THE SURFACE TROUGH WITH SCATTERED
STRONG CONVECTION OCCURRING FROM 20N-24N BETWEEN 81W-88W...AND
FROM 17N-20N BETWEEN 86W-89W OFFSHORE OF THE EASTERN YUCATAN
PENINSULA COAST. THIS SYSTEM IS EXPECTED TO REMAIN FAIRLY
STATIONARY OVER THE NEXT FEW DAYS WITH A VERY BROAD SURFACE LOW
FORECAST TO DRIFT NORTHEASTWARD TOWARDS THE FLORIDA BIG BEND
REGION BY THE WEEKEND WITH A MEDIUM CHANCE OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS OF
DEVELOPMENT...HEAVY RAINS AND LOCALIZED FLOODING ARE POSSIBLE
ACROSS THE YUCATAN PENINSULA...WESTERN CUBA...AND SOUTHERN
FLORIDA THROUGH THE UPCOMING WEEKEND AHEAD.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 07N29W TO 14N24W MOVING W AT 15-20
KT. THE WAVE IS EMBEDDED WITHIN THE MONSOON TROUGH/ITCZ AXIS AND
COINCIDES WITH A VERY WEAK 700-850 MB TROUGH THAT IS ALONG 25W.
NO CONVECTION IS LOCATED IN THE VICINITY OF THE WAVE AXIS AT
THIS TIME DUE TO SAHARAN DUST THAT COVERS MUCH OF THE TROPICAL
NORTH ATLC WATERS PROVIDING OVERALL STABLE CONDITIONS. ANY
CONVECTION TO THE SE OF THE WAVE AXIS IS LIKELY ASSOCIATED WITH
MID-LEVEL DIFFLUENCE AND THE MONSOON TROUGH AXIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
08N27W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
08N27W TO 06N35W TO 08N43W TO 06N58W. SCATTERED MODERATE
CONVECTION IS FROM 05N-11N BETWEEN 17W-24W.

...DISCUSSION...

GULF OF MEXICO...
ASIDE FROM THE SPECIAL FEATURES AREA DESCRIBED ABOVE...THE UPPER
LEVEL LOW CENTERED OVER NORTHERN MEXICO NEAR 27N100W IS ALSO
GENERATING SCATTERED SHOWERS AND TSTMS ACROSS THE WESTERN GULF N
OF 22N W OF 93W DUE TO MAXIMIZED MIDDLE TO UPPER LEVEL
DIFFLUENCE EAST OF THE UPPER LEVEL LOW. THIS UPPER LEVEL FEATURE
IS EXPECTED TO DRIFT WESTWARD THROUGH FRIDAY BUT THEN MERGE
NORTHEASTWARD WITH AN UPPER LEVEL TROUGH EXPECTED TO PROGRESS
OVER THE CENTRAL CONUS INTO THE GREAT LAKES REGION AND LOWER
MISSISSIPPI RIVER VALLEY BY SATURDAY. THE OVERALL WEATHER
SCENARIO OVER THE UPCOMING WEEKEND THOUGH WILL BE DOMINATED BY
THE SPECIAL FEATURES SURFACE TROUGH AND POTENTIAL SURFACE LOW
PRESSURE AREA BRINGING STRONGER CYCLONIC WINDS TO THE EASTERN
GULF OFFSHORE ZONES IN ADDITION TO PLENTY OF CONVECTIVE
PRECIPITATION TO THE EASTERN GULF WATERS AND FLORIDA PENINSULA.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM OVER SOUTHERN MEXICO NEAR
17N97W E-NE TO NEAR 23N81W OVER WESTERN CUBA. UPPER LEVEL
DIFFLUENT FLOW MAXIMIZED OVER PORTIONS OF THE NW CARIBBEAN AND
CUBA GENERATING SCATTERED STRONG CONVECTION NW OF A LINE FROM
17N88W TO 21N78W. THE REMAINDER OF THE CARIBBEAN BASIN IS UNDER
THE INFLUENCE OF NORTH TO NORTHEASTERLY UPPER LEVEL FLOW WEST OF
THE PREVIOUSLY MENTIONED UPPER LEVEL RIDGING. THIS FEATURE IS
PROVIDING FOR AN OVERALL SUBSIDENT ENVIRONMENT OVER THE BASIN S
OF 20N E OF 84W. THE ONLY AREA OF SCATTERED SHOWERS AND ISOLATED
TSTMS ARE IN THE VICINITY OF THE MONSOON TROUGH AXIS EXTENDING
ALONG 09N/10N S OF 10N BETWEEN 75W-81W.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS CENTERED OVER THE SW NORTH ATLC NEAR
28N70W AND SUPPORTS A WEAK SURFACE TROUGH ANALYZED FROM 27N74W
TO 32N64W. WHILE THE SURFACE TROUGH HAS NO SIGNIFICANT
CONVECTION NEAR ITS AXIS...TO THE SOUTH OF THE UPPER LEVEL
LOW...MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED GENERATING
SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS FROM 21N-26N
BETWEEN 67W-78W...AND FROM 22N-28N BETWEEN 63W-67W. TO THE NW OF
THE SURFACE TROUGH...HIGH PRESSURE CONTINUES TO PROVIDE FAIR
WEATHER CONDITIONS AS A 1019 MB HIGH IS CENTERED OFF THE
CAROLINA COAST NEAR 33N72W. OTHERWISE THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1020 MB HIGH CENTERED NEAR 26N45W AND A 1022
MB HIGH CENTERED NEAR 31N28W. ONLY A FEW ISOLATED SHOWERS ARE
OCCURRING ON THE NORTHERN PERIPHERY OF THE RIDGE ACROSS THE
CENTRAL ATLC AS SURFACE TROUGHING STEMMING FROM HURRICANE CHRIS
DIPS SOUTHWARD TO 28N WITH THE CONVECTION WITHIN 150 NM EITHER
SIDE OF A LINE FROM 32N40W TO 26N53W. OF NOTE...EXAMINING THE
GOES-R PROVING GROUND DUST PRODUCT IMAGERY...METEOSAT-9 VISIBLE
IMAGERY...AND THE CIMSS SAHARAN AIR LAYER TRACKING PRODUCT...A
LARGE AREA OF SAHARAN DUST IS ACROSS A LARGE PORTION OF THE
TROPICAL ATLC FROM 09N-24N E OF 42W. ANOTHER AREA OF ENHANCED
SUSPENDED DUST IS ACROSS THE EASTERN CARIBBEAN SEA AND ATLC
WATERS NORTHEAST OF THE LESSER ANTILLES FROM 12N-23N BETWEEN
53W-68W. IMPACTS WILL CONTINUE TO BE HAZY SKY CONDITIONS OVER
THE NEXT FEW DAYS.

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

$$
HUFFMAN




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