[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040005 CCA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 03 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 21N20W TO 10N23W AND IS MOVING W-NW
AT 10 KT. THE WAVE IS NO LONGER INTERACTING WITH THE ITCZ AXIS
AND TOTAL PRECIPITABLE WATER IMAGERY INDICATE THIS WAVE IS
EMBEDDED IN A LOW TO MODERATE MOIST ENVIRONMENT AT THE LOWER
LEVELS. THE METEOSAT-9 SAL TRACKING PRODUCT SHOW THIS WAVE IS
EMBEDDED IN SAL DRY AIR WHICH IS HINDERING CONVECTION.

TROPICAL WAVE IS EMBEDDED WITHIN THE ITCZ AXIS EXTENDING FROM
14N36W TO A 1011 MB LOW NEAR 06N45W...MOVING W-NW NEAR 10 KT.
TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED IN A
HIGH MOIST ENVIRONMENT AT THE LOWER LEVELS. ISOLATED SHOWERS ARE
WITHIN 100 NM WEST OF THE AXIS. CONVECTION ASSOCIATED WITH THIS
WAVE IS LIMITED AT THE MOMENT DUE TO UNFAVORABLE CONDITIONS AT
THE UPPER LEVELS AND SAL DRY AIR CLOSELY ENGULFING THE WAVE
ENVIRONMENT.

TROPICAL WAVE MOVING ACROSS THE EASTERN CARIBBEAN EXTENDING FROM
22N61W TO 13N64W...MOVING W-NW NEAR 10 KT. BOTH TOTAL
PRECIPITABLE WATER IMAGERY AND THE METEOSAT-9 SAL TRACKING
PRODUCT AGREE ON A DRY LOWER TO MIDDLE LEVELS WAVE ENVIRONMENT.
SLIGHT RAINSHOWERS WERE REPORTED DURING THE LAST COUPLE OF HOURS
ASSOCIATED TO THE PASSAGE OF THIS WAVE THROUGHOUT THE LESSER
ANTILLES. CURRENTLY NO CONVECTIVE ACTIVITY IS ASSOCIATED TO THIS
WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
10N15W TO 07N23W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N23W TO 08N30W TO 11N38W. IT RESUMES WEST OF A
TROPICAL WAVE NEAR 05N46W TO NORTHERN BRAZIL NEAR 03N51W.
SCATTERED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF
THE AXIS BETWEEN 17W-26W. BESIDES THE CONVECTION ASSOCIATED WITH
THE WAVE MENTIONED ABOVE...SCATTERED SHOWERS ARE OCCURRING
WITHIN 80 NM WEST OF THE ITCZ AXIS WEST OF 48W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL TROUGH CENTERED OVER THE CENTRAL U.S.
CONTINUE DIPPING INTO THE GULF WEST OF 86W. THIS TROUGH IS
SUPPORTING A FRONTAL SYSTEM N OF THE AREA WHICH TRANSITIONS TO A
SURFACE TROUGH FROM 30N88W TO A 1013 MB LOW NEAR 27N90W TO
22N93W. THE UPPER LEVEL TROUGH ALSO SUPPORTS ANOTHER SURFACE
TROUGH THAT EXTENDS FROM 27N87W TO THE YUCATAN PENINSULA NEAR
21N89W TO THE BAY OF CAMPECHE NEAR 18N91W. IMAGERY FROM RADAR
AND A GOES IR ENHANCEMENT SHOW SCATTERED MODERATE/ISOLATED
STRONG CONVECTION AND ISOLATED THUNDERSTORMS EAST OF 88W. THE
STRONGEST CONVECTION LIES WITHIN 170 NM EAST OF THE EASTERNMOST
SURFACE TROUGH. NUMEROUS STRONG CONVECTION ASSOCIATED WITH THIS
SURFACE TROUGH IS OCCURRING OVER THE YUCATAN PENINSULA AND
EXTENDS WITHIN 70 NM OFF THE PENINSULA WEST COASTLINE. THE
CONVECTION OVER THE EASTERN GULF CONTINUES TO BE ENHANCED BY THE
LOWER LEVELS MOIST AIR THAT HAVE BEEN ADVECTED TO THE GULF FROM
THE WEST CARIBBEAN AND UPPER LEVEL DIFFLUENCE FROM A RIDGE
EXTENDING ALONG FLORIDA TO THE YUCATAN PENINSULA.

WINDS ACROSS THE BASIN RANGE FROM 5-15 KT WITH HIGHER WINDS OF
20 KT EAST OF THE EASTERNMOST TROUGH. CONVECTIVE ACTIVITY OVER
THE EASTERN GULF IS LIKELY TO CONTINUE THROUGH AT LEAST EARLY
FRIDAY AS THE UPPER LEVEL SYNOPTIC FEATURES NEARLY STAY IN
PLACE...HIGH MOISTURE WILL PERSIST AS WELL AS SURFACE TROUGHING.
WITHIN THAT PERIOD...THE LOW IS FORECAST TO DRIFT NORTHEASTWARD.

CARIBBEAN SEA...
EXCEPT FOR THE WESTERN CARIBBEAN W OF 85W...THE CENTRAL
CARIBBEAN S OF LA HISPANIOLA AND THE SOUTHERN CARIBBEAN S OF
12N...TOTAL PRECIPITABLE WATER IMAGERY SHOW VERY DRY AIR AT THE
LOWER LEVELS WHICH IS FAVORING FAIR WEATHER ACROSS MOST OF THE
BASIN. WATER VAPOR IMAGERY SHOW VERY DRY AIR AT THE MIDDLE
LEVELS WHICH REINFORCE A CONVECTIVE FREE ENVIRONMENT. A TROPICAL
WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN JUST EAST OF PUERTO
RICO BUT AS MENTIONED IN THE WAVES DISCUSSION...NO CONVECTION IS
ASSOCIATED WITH IT. SCATTERED SHOWERS ASSOCIATED WITH THE
CONVECTIVE ACTIVITY OVER THE EASTERN GULF ARE N OF 19N W OF 81W.
SCATTERED MODERATE CONVECTION IS OCCURRING FROM 18N-21N BETWEEN
75W-79W. OTHERWISE...15-20 KT TRADEWINDS FLOW ACROSS THE BASIN
WITH THE HIGHEST WINDS MAINLY CENTERED AT THE BASIN.

THE TROPICAL WAVE IS EXPECTED TO MOVE OFF THE WESTERN COAST OF
PUERTO RICO EARLY ON THURSDAY SLIGHT TO NONE CONVECTIVE ACTIVITY
ASSOCIATED WITH IT. NO MAJOR CHANGES ARE EXPECTED FOR THE REST
OF THE BASIN.

HISPANIOLA...
A LOW TO MODERATE MOIST ENVIRONMENT IS ACROSS THE ISLAND AT THE
LOWER LEVELS AT THIS TIME. DIFFLUENT FLOW FROM AN UPPER LEVEL
RIDGE EXTENDING FROM THE EASTERN GULF TO THE CENTRAL CARIBBEAN
AND AN ELONGATED CYCLONIC CIRCULATION N OF THE WINDWARD PASSAGE
IS GENERATING ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE ISLAND.
A TROPICAL WAVE IS EXPECTED TO ENTER THE DOMINICAN REPUBLIC
THURSDAY MORNING INCREASING THE CHANCES OF SHOWERS...ESPECIALLY
AS THE AFTERNOON AND EVENING PROGRESS AS DAYTIME HEATING PEAKS
WITH MAXIMUM INSTABILITY.

ATLANTIC OCEAN...
BESIDES THE TROPICAL WAVES ALREADY MENTIONED ABOVE...BROAD
SURFACE RIDGING COVERS THE ATLC WATERS ANCHORED BY A 1030 MB
HIGH NEAR 35N65W AND THE 1027 MB AZORES HIGH NEAR 36N30W. TOTAL
PRECIPITABLE WATER IMAGERY SHOW VERY DRY AIR ACROSS THE REGION
AT THE LOWER LEVELS WHICH IS SUPPRESSING CONVECTIVE ACTIVITY.

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

$$
RAMOS


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