[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 10 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL WAVE IS ALONG 27W FROM 7N TO 21N WITH A 1009 MB LOW
ALONG THE WAVE NEAR 15N MOVING W NEAR 10 KT. SATELLITE IMAGERY
INDICATES THE LOW/MID LEVEL CYCLONIC CIRCULATION REMAINS...
HOWEVER UPPER LEVEL NORTHERLY WINDS ON THE ERN PERIPHERY OF AN
UPPER LEVEL ANTICYCLONE CENTERED NEAR 19N45W IS BRINGING DRY AIR
ALOFT TO THE WESTERN SIDE OF THE WAVE THUS INHIBITING ANY DEEP
LAYERED CONVECTION. AN AREA OF SCATTERED MODERATE CONVECTION IS
FROM 9N-14N BETWEEN 23W-30W. CONDITIONS APPEAR FAVORABLE FOR
DEVELOPMENT OF THIS SYSTEM AND IT COULD BECOME A TROPICAL
DEPRESSION DURING THE NEXT DAY OR TWO. ASSOCIATED SHOWERS AND
THUNDERSTORMS WITH LOCALLY GUSTY WINDS COULD AFFECT PORTIONS OF
THE CAPE VERDE ISLANDS DURING THE NEXT 24 HOURS. SEE THE
TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20
KNHC FOR ADDITIONAL DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 47W S OF 18N MOVING W NEAR 15 KT. THE
AXIS OF THE WAVE IS ORIENTED WITHIN A MOISTURE MAXIMUM OBSERVED
IN TOTAL PRECIPITABLE WATER IMAGERY AND WELL DEFINED CURVATURE
IN THE LOW LEVEL CLOUDS. SCATTERED MODERATE CONVECTION IS FROM
13N-17N BETWEEN 44W-49W.

TROPICAL WAVE IS FROM ALONG 59W S OF 18N MOVING W NEAR 10 KT. A
1013 MB LOW IS LOCATED ALONG THE WAVE AXIS NEAR 13N AS
OBSERVATIONS AT BARBADOS HAVE BEEN REPORTING A NORTHERLY WIND
COMPONENT THROUGHOUT THE DAY AS THE WAVE/LOW APPROACH FROM THE
EAST. THE WAVE IS LOCATED ALONG A MOISTURE MAXIMUM OBSERVED IN
THE TOTAL PRECIPITABLE WATER IMAGERY. A CLUSTER OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-15N BETWEEN
57W-62W.

TROPICAL WAVE IS ALONG 72W S OF 15N MOVING W NEAR 15 KT. WAVE IS
EMBEDDED WITHIN AN AREA OF MODERATE ELY TRADES OVER THE CENTRAL
CARIBBEAN AND REMAINS DIFFICULT TO DISCERN ON THE LATEST VISIBLE
SATELLITE IMAGERY. DUE TO DRY AND STABLE CONDITIONS ALOFT ACROSS
THE CENTRAL CARIBBEAN THERE IS NO ASSOCIATED SHOWER ACTIVITY OR
CONVECTION WITH THE WAVE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 16N17W 15N25W 11N29W 11N46W
9N49W 13N57W AND INTO THE SE CARIBBEAN ACROSS THE WINDWARD
ISLANDS...ABC ISLANDS TO 12N71W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS INLAND AND WITHIN 150 NM ALONG THE COAST OF
W AFRICA FROM 7N-14N. CLUSTERS OF SIMILAR CONVECTION ARE FROM
7N-11N BETWEEN 30W-39W AND FROM 7N-11N BETWEEN 49W-54W.

...DISCUSSION...

GULF OF MEXICO...
A LARGE UPPER RIDGE IS ANCHORED OFF THE CAROLINA COAST AND
EXTENDS OVER NRN FLORIDA AND NRN GULF TO 91W. DRY AIR ALOFT
ACROSS N FLORIDA AND THE NE GULF N OF 27N IS INHIBITING ANY TSTM
ACTIVITY. HOWEVER...ACROSS THE NW GULF...UPPER LEVEL SWLY FLOW
AND MID-LEVEL INSTABILITY IS FUELING SCATTERED SHOWERS AND TSTMS
MOSTLY N OF 29N AND INLAND ACROSS THE GULF COAST STATES. VERY
WEAK CYCLONIC CURVATURE IN THE LOW TO MIDDLE LEVEL WINDS IS
PROVIDING CONVERGENCE AND GENERATING SCATTERED SHOWERS AND
ISOLATED TSTMS ACROSS THE SW FLORIDA PENINSULA...THE SE GULF
WATERS...AND NRN PORTIONS OF THE YUCATAN PENINSULA S OF 27N AND
E OF 89W. THE ACTIVITY OVER THE YUCATAN PENINSULA IS ALSO BEING
ENHANCED BY AN UPPER LEVEL TROUGH WITH AXIS ACROSS THE
YUCATAN...BELIZE AND GUATEMALA.

CARIBBEAN SEA...
THE W CARIBBEAN IS DOMINATED BY AN UPPER LEVEL TROUGH WITH AXIS
ACROSS THE YUCATAN PENINSULA...BELIZE AND GUATEMALA. DRY AIR
ALOFT IS PROMOTING GENERALLY FAIR WEATHER ACROSS THE NW
CARIBBEAN. OVER THE CENTRAL CARIBBEAN...AN UPPER LEVEL HIGH IS
CENTERED NEAR 17N70W THAT EXTENDS A RIDGE SW TO OVER PANAMA.
MOIST SWLY FLOW BETWEEN THE W CARIBBEAN TROUGH AND CENTRAL
CARIBBEAN RIDGE IS GENERATING SCATTERED SHOWERS AND ISOLATED
TSTMS S OF 17N W OF 80W. THE E CARIBBEAN IS DOMINATED BY THE
AFOREMENTIONED UPPER LEVEL HIGH NEAR ERN HISPANIOLA. VERY DRY
AIR ALOFT IS NOTED OVER MUCH OF THE REGION E OF 74W WITH THE
EXCEPTION BEING ACROSS THE SE CARIBBEAN. LOW-LEVEL MOISTURE AND
INSTABILITY COUPLED WITH THE ITCZ AXIS THAT EXTENDS ACROSS THE
AREA ALONG 12N IS GENERATING SCATTERED SHOWERS AND ISOLATED
TSTMS S OF 14N W OF 68W...INCLUDING THE WINDWARD ISLANDS. A
SMALL AREA OF UPPER DIFFLUENCE IS OVER THE N/CENTRAL CARIBBEAN
GENERATING SCATTERED SHOWERS/ISOLATED TSTMS FROM 18N-21N BETWEEN
71W-78W.

ATLANTIC OCEAN...
THE UPPER RIDGE THAT COVERS THE NE GULF OF MEXICO COVERS THE SW
NORTH ATLC N OF 24N W OF 65W WITH DRY AIR ALOFT SUPPRESSING ANY
SHOWER OR TSTM ACTIVITY. HOWEVER...A NARROW UPPER TROUGH EXTENDS
OVER THE CENTRAL ATLC WITH AXIS FROM 32N54W TO 22N64W. THIS
TROUGH SUPPORTS A COLD FRONT THAT EXTENDS FROM A 1015 MB LOW
CENTERED N OF THE DISCUSSION AREA NEAR 37N49W TO 31N58W AND
CONTINUES INTO THE W ATLC AS A SURFACE TROUGH SW TO 27N69W.
SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS ARE WITHIN 120 NM
S OF THE FRONT AND SURFACE TROUGH. A SECOND WEAKER SURFACE
TROUGH IS TO THE SE AND EXTENDS FROM 27N58W TO 22N62W PRODUCING
A FEW ISOLATED SHOWERS FROM 22N-25N BETWEEN 59W-63W. HIGH
PRESSURE DOMINATES THE W ATLC INTO THE NE GULF OF MEXICO
ANCHORED BY A 1022 MB HIGH NEAR 30N75W AND A SECOND SURFACE
RIDGE OVER THE E ATLC ANCHORED BY A 1028 MB HIGH CENTERED NE OF
THE AZORES. THE SURFACE RIDGE AXIS EXTENDS THROUGH 32N37W TO
24N53W.

$$
HUFFMAN


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