[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT AUG 10 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 12N19W TO 21N18W MOVING W AT 10-15
KT. THE WAVE HAS EMERGED OFF THE COAST OF WEST AFRICA AND
COINCIDES WITH A MID-LEVEL 700 MB TROUGH AXIS ALONG 19W. TOTAL
PRECIPITABLE WATER IMAGERY INDICATES MAXIMUM VALUES FROM 08N-17N
BETWEEN 13W-20W. SCATTERED MODERATE CONVECTION IS FROM 11N-15N
BETWEEN 16W-23W.

TROPICAL WAVE EXTENDS FROM 08N40W TO 20N42W 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 ON THE NORTHERN
EXTENT OF THE WAVE AXIS FROM 17N-25N BETWEEN 40W-45W.

TROPICAL WAVE EXTENDS FROM 19N92W TO 26N88W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH A MIDDLE TO UPPER LEVEL LOW CENTERED
OVER THE WESTERN GULF OF MEXICO NEAR 23N90W THAT IS PROVIDING A
BROAD OVERALL CYCLONIC MOTION TO CLOUDS AND PRECIPITATION ACROSS
THE GULF BASIN THIS AFTERNOON. WHILE IT IS DIFFICULT TO
DIFFERENTIATE CONVECTION ASSOCIATED WITH THE UPPER LEVEL LOW AND
THE TROPICAL WAVE AXIS...WIDELY SCATTERED MODERATE CONVECTION IS
OCCURRING OVER THE SE GULF FROM 22N-28N BETWEEN 82W-91W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO
11N22W TO 07N42W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N42W TO 06N47W TO 08N59W. ASIDE FROM CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE EMERGING OFF THE WEST AFRICA
COAST ALONG 19W...SCATTERED MODERATE CONVECTION IS FROM 07N-11N
BETWEEN 16W-20W...AND FROM 04N-09N BETWEEN 25W-29W. ISOLATED
MODERATE CONVECTION IS FROM 07N-11N BETWEEN 55W-62W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL LOW IS
CENTERED OVER THE WESTERN GULF NEAR 23N90W THAT CONTINUES TO
ADVECT MOISTURE OVER MUCH OF THE EASTERN AND CENTRAL GULF.
MIDDLE TO UPPER LEVEL DIFFLUENCE ALONG WITH A TROPICAL WAVE
ANALYZED ALONG 90W IS PRODUCING WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 22N-28N BETWEEN 81W-92W. WHILE THE TROPICAL
WAVE IS CERTAINLY IMPACTING CYCLONIC FLOW IN THE LOWER-
LEVELS...IT APPEARS THE UPPER LEVEL LOW CONTINUES AS THE MORE
DOMINATE FEATURE. TO THE WEST ALONG COASTAL SOUTHERN TEXAS AND
COASTAL EASTERN MEXICO...A TROUGH OF LOW SURFACE PRESSURE IS
ANCHORED BY A 1011 MB LOW CENTERED NEAR 23N96W. THE SURFACE
TROUGH EXTENDING FROM THE TEXAS COAST NEAR 28N97W TO THE LOW
CENTER THEN SE TO THE SOUTHERN MEXICO COAST NEAR 19N93W. WITH A
SURFACE LOW IN PLACE AND THE MAXIMUM MIDDLE TO UPPER LEVEL
DIFFLUENCE OVER THE SW GULF...SCATTERED SHOWERS AND TSTMS ARE
OCCURRING WEST OF A LINE FROM THE TEXAS/LOUISIANA COAST NEAR
30N94W TO THE MEXICO COAST NEAR 19N92W. MOST OF THE CONVECTION
IS OCCURRING OVER THE OFFSHORE WATERS...HOWEVER A FEW WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING INLAND OVER
EAST-CENTRAL MEXICO FROM 19N-25N E OF 100W. THE SURFACE
TROUGHING ACROSS THE WESTERN GULF IS EXPECTED TO VERY SLOWLY
DRIFT WESTWARD AND WEAKEN OVER THE NEXT 24 TO 36 HOURS WITH
PRIMARILY E-SE WINDS IN THE RANGE OF 10 TO 20 KT PREVAILING OVER
THE GULF THROUGH EARLY TUESDAY.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN CARIBBEAN NEAR 17N79W AND IS PROVIDING AN OVERALL
DIFFLUENT ATMOSPHERE ALOFT W OF 70W. AT THE SURFACE...E-SE WINDS
PREVAIL WITH AREAS OF LOW-LEVEL CONVERGENCE THAT CONTINUE TO
GENERATE WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS S OF 20N
BETWEEN 70W-83W. ACROSS THE SW CARIBBEAN AND PORTIONS OF INLAND
CENTRAL AMERICA...THE MOISTURE CONVERGENCE IS MARGINALLY
STRONGER SPARKING SCATTERED SHOWERS AND TSTMS S OF 15N BETWEEN
80W-86W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NE OF THE
LEEWARD ISLANDS NEAR 18N59W. PRIMARILY NW WINDS ALOFT DOMINATE E
OF 70W WITH THE BASE OF THE TROUGH LOCATED OVER THE WINDWARD
ISLANDS NEAR 12N61W. WHILE LOW-LEVEL MOISTURE CONVERGENCE IS
GENERATING ISOLATED SHOWERS AND TSTMS BETWEEN 62W-70W...THE
MIDDLE TO UPPER LEVEL DYNAMICS BECOME STRONGER E OF 62W AND ARE
GENERATING SCATTERED SHOWERS AND TSTMS 11N-17N BETWEEN 53W-62W.
MOST OF THE STRONGEST CONVECTION REMAINS DIRECTLY EAST OF SAINT
LUCIA ALONG 14N AT THIS TIME.

HISPANIOLA...
CURRENTLY A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS
THE ISLAND WITH THE MOST INTENSE AREAS OF THIS CONVECTION
LOCATED WITHIN THE NORTHERN AND SOUTHERN ADJACENT COASTAL WATERS
REGIONS. 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
OVER A LARGE PORTION OF THE SW NORTH ATLC THAT CONTINUES TO
SUPPORT A SURFACE RIDGE OF HIGH PRESSURE ANCHORED BY A 1022 MB
HIGH CENTERED NEAR 31N69W. THE SURFACE RIDGE AXIS EXTENDS
WESTWARD TO THE FLORIDA PENINSULA NEAR JACKSONVILLE AND E-NE TO
BEYOND 33N60W. MOSTLY CLEAR SKIES AND FAIR CONDITIONS ACCOMPANY
THIS FEATURE W OF 50W...HOWEVER A FEW ISOLATED SHOWERS AND TSTMS
ARE OCCURRING IN THE VICINITY OF 28N66W. 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 1031 MB HIGH CENTERED NORTH OF THE AZORES NEAR
41N26W. ALSO OF NOTE...WHILE THE TROPICAL WAVES ARE DISCUSSED IN
DETAIL ABOVE...BETWEEN THE WAVES A LARGE AREA OF SAHARAN DUST IS
LOCATED GENERALLY N OF 10N E OF 40W.

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

$$
HUFFMAN


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