[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111758
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 11 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 12N24W TO 20N23W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A BROAD LOW-LEVEL SURFACE CIRCULATION
FOCUSED IN THE VICINITY OF A 1010 MB LOW CENTERED NEAR 12N24W.
IN ADDITION...A MID-LEVEL 700 MB TROUGH AXIS ALSO EXTENDS FROM
12N24W NORTHWARD TO ALONG THE WAVE AXIS TO 20N23W. TOTAL
PRECIPITABLE WATER IMAGERY INDICATES MAXIMUM VALUES FROM 08N-22N
BETWEEN 15W-26W. CONVECTION REMAINS LARGELY EMBEDDED WITHIN THE
MONSOON TROUGH AXIS WITH SCATTERED MODERATE FROM 08N-12N BETWEEN
21W-28W.

TROPICAL WAVE EXTENDS FROM 07N43W TO 18N47W MOVING W AT 15-20
KT. THE WAVE REMAINS ON THE LEADING EDGE OF SAHARAN DUST WHICH
IS NOTED ON VISIBLE SATELLITE IMAGERY TO THE EAST OF THE WAVE
AXIS. THIS SAHARAN AIR LAYER IS INHIBITING ANY DEEP CONVECTION
AND RESULTING IN ONLY A FEW POSSIBLE SHOWERS IN THE VICINITY OF
THE SOUTHERN PORTION OF THE WAVE FROM 04N-09N BETWEEN 40W-48W
WHICH REMAINS EMBEDDED WITHIN THE MONSOON TROUGH AXIS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO
12N24W TO 06N44W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 06N44W TO 05N49W TO 06N57W. ASIDE FROM CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE ALONG 24W...WIDELY SCATTERED
MODERATE CONVECTION IS FROM 06N-13N BETWEEN 14W-28W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL LOW IS
CENTERED OVER THE WESTERN GULF NEAR 23N96W THAT CONTINUES TO
CARRY WITH IT MOISTURE GENERALLY W OF 85W. WHILE SURFACE RIDGING
REMAINS ANCHORED OVER THE SW NORTH ATLC REGION...MOSTLY E-SE
WINDS PREVAIL OVER THE BASIN THIS AFTERNOON. THE EXCEPTION IS
THE PRESENCE OF A SURFACE TROUGH ANALYZED FROM THE TEXAS COAST
NEAR 28N97W SOUTHWARD INTO A 1013 MB LOW NEAR 21N96W THEN SE TO
THE SOUTHERN MEXICO COAST NEAR 18N93W. LOW-LEVEL MOISTURE
CONVERGENCE ALONG WITH THE UPPER LEVEL DYNAMICS PROVIDED BY THE
WESTWARD MOVING UPPER LEVEL LOW ARE GENERATING SCATTERED SHOWERS
AND TSTMS S OF 26N W OF 92W...WITH ISOLATED SHOWERS AND TSTMS
OCCURRING ELSEWHERE W OF 86W. THE SURFACE TROUGHING ACROSS THE
WESTERN GULF IS EXPECTED TO SLOWLY DRIFT WESTWARD AND DISSIPATE
OVER THE NEXT 24 HOURS WITH PRIMARILY E-SE WINDS IN THE RANGE OF
10 TO 20 KT PREVAILING OVER THE GULF THROUGH EARLY TUESDAY.
THEREAFTER...A RIDGE AXIS IS FORECAST TO ANCHOR ALONG 27N UNTIL
FRIDAY.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN CARIBBEAN NEAR 14N81W AND IS PROVIDING AN OVERALL
DIFFLUENT AND UNSTABLE ATMOSPHERE ALOFT W OF 75W. AT THE
SURFACE...E-SE WINDS PREVAIL WITH AREAS OF LOW-LEVEL MOISTURE
CONVERGENCE THAT CONTINUE TO GENERATE WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS ACROSS THE NW CARIBBEAN N OF 16N W OF
76W...INCLUDING BELIZE...INLAND PORTIONS OF THE SE YUCATAN
PENINSULA...AND NORTHERN GUATEMALA. ACROSS THE SW CARIBBEAN AND
PORTIONS OF INLAND CENTRAL AMERICA...THE MOISTURE CONVERGENCE IS
MARGINALLY STRONGER WITH SCATTERED SHOWERS AND TSTMS S OF 14N
BETWEEN 70W-85W. SOME OF THIS CONVECTION IS LIKELY ENHANCED DUE
TO CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ANALYZED ALONG
10N. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED N OF
HISPANIOLA NEAR 21N72W WITH A TROUGH AXIS EXTENDING E-SE TO
20N64W. PRIMARILY W-NW WINDS ALOFT DOMINATE E OF 80W WITH THE
BASE OF THE TROUGH LOCATED OVER THE SE CARIBBEAN NEAR 14N64W.
WHILE LOW-LEVEL MOISTURE CONVERGENCE IS GENERATING ISOLATED
SHOWERS AND TSTMS BETWEEN 65W-75W...THE MIDDLE TO UPPER LEVEL
DYNAMICS BECOME STRONGER E OF 65W...PARTICULARLY A 700 MB TROUGH
AXIS EXTENDING FROM 19N63W TO 13N67W...AND ARE GENERATING
SCATTERED SHOWERS AND TSTMS 11N-19N BETWEEN 56W-65W.
PRECIPITATION HAS PERSISTED ACROSS THE LESSER ANTILLES AND
EASTERN CARIBBEAN OVER THE PAST DAY OR SO WITH 24 HOUR
PRECIPITATION TOTALS FOR GUADELOUPE REGISTERING 1.71 INCHES AND
0.93 INCHES FOR TRINIDAD COVERING THE 07/1200 UTC TO 08/1200 UTC
TIME FRAME.

HISPANIOLA...
CURRENTLY CONDITIONS REMAINS FAIR THIS EARLY AFTERNOON ACROSS
THE ISLAND WITH A FEW ISOLATED SHOWERS OCCURRING MOSTLY IN THE
NORTHERN ADJACENT COASTAL WATERS. UPPER LEVEL WINDS ARE
NORTHWESTERLY ALOFT AND WATER VAPOR IMAGERY INDICATES A FAIRLY
DRY AIRMASS IN PLACE THAT IS EXPECTED TO STAY OVER THE REGION
THE NEXT FEW DAYS. HOWEVER WITH E-SE WINDS PERSISTING ACROSS
MUCH OF THE CARIBBEAN SEA AND SW NORTH ATLC WATERS THIS
AFTERNOON AND EVENING...AND PEAK DAYTIME HEATING AND STABILITY
TO OCCUR WITHIN THE NEXT FEW HOURS...SCATTERED SHOWERS AND TSTMS
ARE POSSIBLE THROUGH LATE EVENING.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
NEAR 30N78W THAT INFLUENCES A LARGE PORTION OF THE SW NORTH ATLC
THIS AFTERNOON. THE RIDGING ALOFT CONTINUES TO SUPPORT A SURFACE
RIDGE OF HIGH PRESSURE ANCHORED BY A 1022 MB HIGH CENTERED NEAR
29N76W. THE SURFACE RIDGE AXIS EXTENDS WESTWARD TO THE FLORIDA
PENINSULA AND EASTWARD INTO THE CENTRAL ATLC. MOSTLY FAIR SKIES
AND CONDITIONS ACCOMPANY THIS FEATURE W OF 55W...HOWEVER A FEW
ISOLATED SHOWERS CONTINUE TO DRIFT WESTWARD UNDER LIGHT EASTERLY
SURFACE FLOW. THE MORE CONCENTRATED SHOWER ACTIVITY IS FOCUSED
OVER THE BAHAMAS AND TURKS AND CAICOS ISLANDS S OF 26N BETWEEN
70W-77W THIS AFTERNOON. FARTHER EAST ACROSS THE CENTRAL AND
EASTERN ATLC...FAIRLY BENIGN CONDITIONS ARE NOTED ON SATELLITE
IMAGERY AS A SURFACE RIDGE DOMINATES. THE RIDGING IS ANCHORED BY
A 1026 MB HIGH CENTERED SW OF THE AZORES NEAR 34N33W. THE ONLY
COMPROMISE OF THE SURFACE RIDGING IS A SURFACE TROUGH ANALYZED
FROM 24N47W TO 28N47W WHICH IS SUPPORTED ALOFT BY AN UPPER LEVEL
LOW AND MID-LEVEL SHORTWAVE TROUGHING IN THE VICINITY OF 27N52W.
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM
24N-29N BETWEEN 45W-50W. ALSO OF NOTE...WHILE THE TROPICAL WAVES
ARE DISCUSSED IN DETAIL ABOVE...BETWEEN THE WAVES AN AREA OF
SAHARAN DUST IS LOCATED GENERALLY N OF 12N BETWEEN 25W-45W.

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

$$
HUFFMAN


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