[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 31 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
1722 UTC.

...TROPICAL WAVES...
TROPICAL WAVE AXIS IN THE TROPICAL ATLC EXTENDS FROM 18N43W TO
13N42W 09N40W MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN A
NARROW SURGE OF MODERATE MOISTURE AS DEPICTED IN TOTAL
PRECIPITABLE WATER IMAGERY. THE METEOSAT-9 SAL TRACKING PRODUCT
SHOWS THE WAVE IS AT THE LEADING EDGE OF A SAHARAN AIR LAYER
OUTBREAK WITH VERY DRY AIR WHICH IS HINDERING CONVECTION.

AS OF 1500 UTC...TROPICAL WAVE AXIS EXTENDS FROM 27N80W TO
19N82W MOVING W-NW NEAR 10-15 KT. TOTAL PRECIPITABLE WATER
IMAGERY SHOW THE WAVE IS EMBEDDED WITHIN A MODERATE MOIST
ENVIRONMENT WITH SOME DRIER AIR OVER THE PORTION OF THE WAVE
LYING OVER THE FLORIDA PENINSULA. UPPER LEVEL DIFFLUENCE FROM A
LOW OVER THE SW N ATLC AND A HIGH OVER SE NEW MEXICO EXTENDING A
RIDGE THROUGH THE GULF AND FLORIDA PENINSULA IS ENHANCING
SCATTERED RAINSHOWERS AND ISOLATED TSTMS OVER THE SE GULF
INCLUDING THE FLORIDA STRAITS...OVER WESTERN CUBA...AS WELL AS
WITHIN 170 NM E OF THE WAVE AXIS S OF 22N.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 15N16W AND CONTINUES ALONG 08N28W TO 05N38W.
THE ITCZ BEGINS NEAR 05N38W AND CONTINUES ALONG 05N47W 06N57W.
SCATTERED MODERATE CONVECTION WITH ISOLATED TSTMS IS SE OF A
LINE FROM 17N18W TO 06N22W. A CLUSTER OF MODERATE CONVECTION IS
FROM 04N-08N BETWEEN 29W-33W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...SURFACE RIDGING DOMINATES ACROSS MOST OF THE
GULF N OF 21N WITH RETURN FLOW IN THE RANGE OF 5-10 KT MOVING
AROUND A 1022 MB HIGH NEAR 27N87W. UPPER LEVEL DIFFLUENCE FROM A
LOW OVER THE SW N ATLC AND A HIGH OVER SE NEW MEXICO EXTENDING A
RIDGE THROUGH THE GULF AND FLORIDA PENINSULA IS ENHANCING
SCATTERED RAINSHOWERS AND ISOLATED TSTMS OVER THE SE GULF
INCLUDING THE FLORIDA STRAITS. A PREFRONTAL TROUGH EXTENDS
ACROSS NORTHERN FLORIDA INTO THE NE GULF ALONG 29N83W TO 26N85W
GENERATING ISOLATED SHOWERS AND TSTMS WITHIN 70 NM EITHER SIDE
OF THE AXIS. A WEAK SURFACE TROUGH IS OVER THE BAY OF CAMPECHE
FROM 21N92W TO 16N93W WITH NO CONVECTION ASSOCIATED WITH IT.
OTHERWISE...DRY AIR IN THE LOWER AND MIDDLE LEVELS IS SUPPORTING
FAIR WEATHER OVER THE REMAINDER BASIN W OF 88W.

HIGH PRESSURE IS EXPECTED TO CONTINUE OVER THE NORTHERN GULF
DURING THE NEXT 48 HOURS. THE TROPICAL WAVE MOVING ACROSS
SOUTHERN FLORIDA AND THE WESTERN CARIBBEAN IS EXPECTED TO ENTER
THE SE GULF THIS EVENING AND CONTINUE MOVING WESTWARD TOWARDS
THE SW GULF THROUGH THURSDAY. RAINSHOWERS ACTIVITY IS EXPECTED
DURING THIS PERIOD ACROSS THE SOUTHERN BASIN.

CARIBBEAN SEA...
AS OF 1500 UTC...A TROPICAL WAVE IS MOVING ACROSS THE SOUTHERN
FLORIDA PENINSULA AND WESTERN CARIBBEAN ENHANCING ISOLATED
SHOWERS AND TSTMS N OF 18N W OF 78W. A SURFACE TROUGH IS NOW
ANALYZED FROM 26N72W TO 18N75W ASSOCIATED WITH REMNANT
CONVECTION FROM DORIAN. SCATTERED MODERATE CONVECTION AND TSTMS
ARE AFFECTING THE SOUTHERN BAHAMAS AS WELL...CENTRAL AND EASTERN
CUBA...THE WINDWARD PASSAGE AND NORTHERN HISPANIOLA. ANOTHER
SURFACE TROUGH IS ANALYZED FROM 20N63W TO 16N66W JUST E OF
PUERTO RICO. SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH THIS
TROUGH ARE FROM 17N-20N BETWEEN 61W-66W. THE LEEWARD ISLANDS
HAVE BEEN REPORTING RAINSHOWERS AND RADAR IMAGERY FROM PUERTO
RICO SHOW SIMILAR ACTIVITY ACROSS THE SOUTHERN PART OF THE
ISLAND. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE
OVER THE SOUTHERN GULF S OF 14N W OF 80W ASSOCIATED WITH THE
MONSOON TROUGH WHICH AXIS MOVES ACROSS COSTA RICA AND PANAMA.
TRADEWINDS OF 10-15 KT SPREAD OVER MOST OF THE BASIN WITH HIGHER
WINDS UP TO 25 KT NEAR THE COAST OF COLOMBIA. OTHERWISE...DRY
AIR IN THE LOWER AND MIDDLE LEVELS IS SUPPORTING FAIR WEATHER IN
THE REMAINDER BASIN.

THE TROPICAL WAVE MOVING ACROSS SOUTHERN FLORIDA AND THE WESTERN
CARIBBEAN IS EXPECTED TO ENTER THE SE GULF THIS EVENING AND
CONTINUE MOVING WESTWARD TOWARDS THE SW GULF THROUGH THURSDAY.
THE TROUGH AND REMNANT CONVECTION ASSOCIATED WITH DORIAN WILL
CONTINUE TO MOVE WESTWARD ACROSS THE BAHAMAS IN THE NEXT 24
HOURS AND RAINSHOWERS ARE EXPECTED TO CONTINUE AFFECT CUBA
THROUGH EARLY THURSDAY. THE SURFACE TROUGH E OF PUERTO RICO WILL
MOVE ACROSS THE ISLAND TODAY WITH MOST OF ITS CONVECTION STAYING
OFFSHORE N OF THE ISLAND.

HISPANIOLA...
ISOLATED RAINSHOWERS AND TSTMS ARE OCCURRING ACROSS NORTHERN
HISPANIOLA ASSOCIATED WITH A SURFACE TROUGH AND REMNANT
CONVECTION FROM DORIAN. SHOWERS ARE EXPECTED TO CONTINUE
OVERNIGHT. CONDITIONS IMPROVE THURSDAY MORNING BUT DETERIORATE
IN THE AFTERNOON AS THE SURFACE TROUGH CURRENTLY E OF PUERTO
RICO MOVES ACROSS THE ISLAND.

ATLANTIC OCEAN...
BESIDES THE CONVECTION ALREADY DISCUSSED ASSOCIATED WITH THE
REMNANTS OF DORIAN...THE SURFACE TROUGH E OF PUERTO RICO AND THE
TROPICAL WAVE...A SURFACE TROUGH EXTENDS FROM 30N53W TO 29N59W
27N65W WITH ISOLATED SHOWERS AND TSTMS WITHIN 100 NM EITHER SIDE
OF ITS AXIS. ANOTHER SURFACE TROUGH EXTENDS ALONG 28N50W TO
16N52W WITH NO CONVECTION ASSOCIATED WITH IT. OTHERWISE...A 1025
MB HIGH IS NEAR 29N39W. FAIR WEATHER IS ACROSS THE EASTERN ATLC
AS OF VERY DRY AIR FROM A SAL OUTBREAK SPREADS ACROSS THAT PART
OF THE BASIN.

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

$$
RAMOS


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