[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061806
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 06 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.

...SPECIAL FEATURES...
THE 1012 MB LOW PRESSURE ASSOCIATED WITH THE TROPICAL WAVE OVER
THE EASTERN ATLC HAS BECOME BETTER ORGANIZED WITHIN THE LAST
COUPLE OF HOURS AND HAS A MEDIUM CHANCE OF DEVELOPMENT WITHIN
THE NEXT 48 HOURS. SEE THE TROPICAL WAVES SECTION BELOW FOR MORE
INFORMATION ABOUT THE WAVE ASSOCIATED WITH THIS LOW.

...TROPICAL WAVES...
A TROPICAL WAVE IS MOVING W NEAR 20 KT WITH AXIS EXTENDING FROM
18N39W TO A 1012 MB LOW EMBEDDED WITHIN THE MONSOON TROUGH AXIS.
EXCEPT FOR THE PORTION  OF THE WAVE ASSOCIATED WITH THE
LOW...VERY DRY AIR FROM A SAL OUTBREAK SPREADS OVER ITS
ENVIRONMENT WHICH IS HINDERING CONVECTION N OF 9N. A CLUSTER OF
MODERATE CONVECTION IS FROM 04N-09N BETWEEN 32W-36W ASSOCIATED
WITH THE LOW.

A TROPICAL WAVE IS MOVING W-NW NEAR 15 KT ACROSS THE EASTERN
CARIBBEAN. CURRENTLY ITS AXIS EXTENDS FROM 21N61W TO 13N68W AND
IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT AS DEPICTED IN TOTAL
PRECIPITABLE WATER IMAGERY. A MORE MOIST AREA LIES FARTHER EAST
WHERE THE WAVE WAS PREVIOUSLY ANALYZED. WIDESPREAD DUST HAS BEEN
REPORTED IN THE LESSER ANTILLES AS WELL AS IN DOMINICAN REPUBLIC
AND DRY AIR IS OBSERVED SURROUNDING THE WAVE ENVIRONMENT IN
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION
AND ISOLATED THUNDERSTORMS ARE FROM 18N-20N WITHIN 250 NM E OF
THE WAVE AXIS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE FROM AN
UPPER CYCLONIC CIRCULATION CENTERED NEAR 23N66W AND AN
ANTICYCLONIC CIRCULATION CENTERED 12N58W. RADAR IMAGERY FROM
PUERTO RICO SHOW ISOLATED SHOWERS N OF 16N E OF 68W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE WEST COAST OF AFRICA NEAR
19N16W TO 11N23W TO A 1012 MB SURFACE LOW NEAR 06N33W TO 06N36W.
THE ITCZ BEGINS NEAR 06N36W AND CONTINUES ALONG 05N49W 06N57W.
BESIDES CONVECTION NEAR THE SURFACE LOW ASSOCIATED WITH THE
TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 06N-12N E
OF 19W. SIMILAR CONVECTION IS WITHIN 180 NM S OF THE ITCZ AND
WITHIN 80 NM N OF THE AXIS W OF 39W.

...DISCUSSION...

GULF OF MEXICO...
ABUNDANT MOISTURE IS BASIN WIDE WITH A MAXIMUM S OF 27N W OF
90W. THIS MOISTURE IS DUE TO A COMBINATION OF MOIST SOUTHERLY TO
SOUTHEASTERLY FLOW AT THE SURFACE THROUGHOUT MUCH OF THE
AREA...AND MOIST SOUTHWESTERLY AND DIFFLUENT FLOW ALOFT BETWEEN
AN UPPER LEVEL TROUGH OVER THE CENTRAL CONUS THAT IS PUSHING
INTO THE NW GULF...AND AN UPPER LEVEL RIDGE OVER THE REMAINDER
OF THE BASIN EXTENDING FROM THE BAY OF CAMPECHE TO NORTHERN
FLORIDA. THE UPPER LEVEL TROUGH IS SUPPORTING A SURFACE TROUGH
THAT EXTENDS FROM SOUTHERN ALABAMA NEAR 30N88W...ACROSS SE
LOUISIANA TO 29N91W 26N96W TO TAMPICO MEXICO. NUMEROUS
MODERATE/ISOLATED STRONG CONVECTION AND THUNDERSTORMS
CONCENTRATE E OF THE SURFACE TROUGH AXIS W OF 90W. SCATTERED
MODERATE CONVECTION AND ISOLATED THUNDERSTORMS ARE N OF 21N
BETWEEN 84W-90W. OTHERWISE...RETURN FLOW OF 15-25 KT SPREADS
EAST OF THE SURFACE TROUGH BEING THE STRONGEST WINDS W OF 90W.

ABUNDANT MOISTURE WILL PERSIST OVER THE GULF WITH THE HIGHEST
CONCENTRATION BEING OVER THE WESTERN GULF AS RETURN FLOW
COMPLETELY BUILDS ACROSS THE BASIN AND THE UPPER LEVEL RIDGE
CONTINUES TO SHIFT W-NW. RAINSHOWERS ACROSS THE BASIN ARE
EXPECTED UNTIL MONDAY MORNING WHEN DRIER AIR ENTERS THE REGION.

CARIBBEAN SEA...
MOISTURE FROM THE GULF OF MEXICO IS BEING DRAWN OVER THE NW
CARIBBEAN IN NORTHERLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE
OVER THE GULF. ONLY A FEW ISOLATED SHOWERS ARE NORTH OF 18N W OF
73W. SCATTERED MODERATE CONVECTION AND ISOLATED THUNDERSTORMS
ARE IN THE SW CARIBBEAN S OF 13N W OF 77W ASSOCIATED WITH THE
MONSOON TROUGH AXIS WHICH MOVES ACROSS PANAMA TO A 1008 MB
SURFACE LOW OVER NORTHERN COLOMBIA. A TROPICAL WAVE AXIS IS JUST
EAST OF PUERTO RICO AND WILL BE MOVING ACROSS THE ISLAND TODAY.
CURRENTLY SCATTERED MODERATE CONVECTION AND ISOLATED
THUNDERSTORMS ARE FROM 18N-20N WITHIN 250 NM E OF THE WAVE AXIS
BEING ENHANCED BY UPPER LEVEL DIFFLUENCE FROM AN UPPER CYCLONIC
CIRCULATION CENTERED NEAR 23N66W AND AN ANTICYCLONIC CIRCULATION
CENTERED 12N58W. RADAR IMAGERY FROM PUERTO RICO SHOW ISOLATED
SHOWERS N OF 16N E OF 68W. DRY AIR AT LOWER AND MIDDLE LEVELS IS
ACROSS THE REMAINDER BASIN AS DEPICTED IN TOTAL PRECIPITABLE
WATER AND WATER VAPOR IMAGERY. OTHERWISE...TRADEWINDS FLOW OF 15-
20 KT IS THROUGHOUT MUCH OF THE AREA WITH STRONGER WINDS TO 25
KT OVER THE CENTRAL CARIBBEAN AND NEAR THE COAST OF COLOMBIA.

THE WAVE OVER THE EASTERN CARIBBEAN IS EXPECTED TO MOVE OFF
PUERTO RICO VERY EARLY ON SUNDAY. RAINSHOWERS CAN BE EXPECTED
THROUGHOUT THE DAY.

HISPANIOLA...
CURRENTLY VERY DRY AIR IS ACROSS THE ISLAND AS DEPICTED IN TOTAL
PRECIPITABLE WATER AND WATER VAPOR IMAGERY. IN
ADDITION...DOMINICAN REPUBLIC HAS BEEN REPORTING WIDESPREAD DUST
OVER THE PAST SEVERAL HOURS. HOWEVER RAINSHOWERS COULD BE
POSSIBLE THIS AFTERNOON ENHANCED BY DAYTIME HEATING. WEATHER
CONDITIONS WILL START TO DEGRADE VERY EARLY ON SUNDAY AS A
TROPICAL WAVE MOVES OVER THE WINDWARD PASSAGE TOWARDS THE
DOMINICAN REPUBLIC. UPPER LEVEL DIFFLUENT FLOW SHIFTING WESTWARD
ALONG WITH THE WAVE AS WELL AS MODERATE MOISTURE ARE LIKELY TO
ENHANCE RAINSHOWERS ACROSS THE ISLAND ON SUNDAY. WEATHER
CONDITIONS ARE EXPECTED TO IMPROVE EARLY ON MONDAY.

ATLANTIC OCEAN...
BROAD SURFACE RIDGING DOMINATES THE WEST ATLC AROUND A 1027 MB
HIGH NEAR 34N71W. THE RIDGE IS SUPPORTED BY BROAD UPPER RIDGING
CENTERED NEAR 35N69W. AN UPPER LEVEL LOW IS CENTERED NEAR 23N66W
SUPPORTING A FEW ISOLATED SHOWERS FROM 21N-26N BETWEEN 63W-70W.
A TROPICAL WAVE IS TO THE EAST SUPPORTING SCATTERED MODERATE
CONVECTION AND ISOLATED THUNDERSTORMS FROM 18N-20N WITHIN 250 NM
E OF THE WAVE AXIS. A STATIONARY FRONT TO THE NORTH EXTENDS INTO
THE AREA ALONG 30N42W TO 29N46W 29N52W 29N56W 29N59W. SCATTERED
MODERATE CONVECTION IS N OF 27N BETWEEN 41W-45W...ISOLATED
SHOWERS ARE N OF 28N BETWEEN 58W-63W. VERY DRY AIR IS THROUGHOUT
THE EAST ATLC DUE TO A SAHARAN AIR LAYER OUTBREAK.

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

$$
RAMOS


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