[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI MAY 23 2014

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS NOTED OFF THE COAST OF WEST AFRICA ALONG 19W
FROM 04N TO 10N. THE WAVE HAS A WELL DEFINED LOWER TO MID LEVEL
CIRCULATION CENTERED NEAR 06N19W. THE WAVE IS REPRESENTED POORLY
OVER THE WAVE INDICATED VERY LIGHT SURFACE WINDS WITH NO
DISCERNIBLE CYCLONIC TURNING IN A RECENT ASCAT SATELLITE PASS.
THE SURFACE WIND PATTERN SUGGESTS THAT THE WAVE IS LOCATED JUST
TO THE EAST OF WELL DEFINED CONFLUENT FLOW THAT FORMS THE START
OF THE ITCZ EXTENDING FARTHER TO THE WEST. A BROAD AREA OF
SHOWERS AND THUNDERSTORMS ARE NOTED ACCORDINGLY JUST TO THE WEST
OF THE WAVE AXIS. THE WAVE IS RELATED TO ANOTHER CIRCULATION
FARTHER NORTH THAT MOVED OFF THE COAST OF SENEGAL A COUPLE OF
DAYS AGO BUT HAS SINCE WEAKENED. LOOKING AHEAD...GFS OUTPUT
SHOWS THE WAVE AT H7 AS FAIRLY LOW AMPLITUDE AND LOW LATITUDE
INTO SUNDAY AS IT DRIFTS WESTWARD...BUT MAY AMPLIFY NEAR 40W BY
LATE SUNDAY AS IT STARTS TO INTERACT WITH AN UPPER TROUGH N OF
THE AREA.

A SECOND TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC ALONG
SHOWED SUBTLE CYCLONIC TURNING IN THIS AREA AT THE
SURFACE...ENHANCING AN AREA OF 20 KT TRADES ON THE NORTH END OF
THE WAVE. THE WAVE IS RIDING THE CUSP OF DEEP MOISTURE NOTED IN
SSMI PRECIPITABLE WATER COMPOSITE IMAGERY. THE WAVE IS TO THE SW
CORNER OF A BROAD MID/UPPER RIDGE EXTENDING ALONG ROUGHLY 10N
AND TOWARD AN AREA OF MORE FAVORABLE UPPER FLOW BETWEEN THE
RIDGE AND A BROAD MID LATITUDE MID/UPPER TROUGH TO THE
NORTHEAST. THE WAVE WILL THUS AMPLIFY SLIGHT AND SLOW DOWN AS IT
MOVES INTO NE SOUTH AMERICA AND THE FAR SOUTHERN WINDWARD
ISLANDS THROUGH THE WEEKEND...FOLLOWED BY INCREASED TRADES.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH REACHES ACROSS WEST AFRICA ALONG 13N BUT IS
INTERRUPTED BY THE TROPICAL WAVE BEFORE IT REACHES THE ATLANTIC
COAST. THE ITCZ STARTS WEST OF THE TROPICAL WAVE AT 04N21W AND
REACHES SW TO THE COAST OF BRAZIL NEAR 01S45W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM
N AND 240 NM S OF THE ITCZ W OF 25W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL RIDGING REMAINS IN PLACE ACROSS THE
WESTERN GULF ALONG 95W...TO THE WEST OF A BROAD TROUGH OVER THE
SW NORTH ATLANTIC. AN ASSOCIATED 1020 MB SURFACE HIGH IS
ANCHORED OVER THE NE GULF NEAR 28N87W...MAINTAINING GENERALLY
LIGHT TO MODERATE FLOW ACROSS THE BASIN. THE ONLY EXCEPTION IS
15 TO 20 KT NE TO E WINDS RELATED TO THE TYPICAL OVERNIGHT
TROUGH OFF THE WEST COAST OF THE YUCATAN PENINSULA. DEEP LAYER
DRY AIR AND WIND SHEAR CONTINUE TO SUPPORT FAIR WEATHER AND
CLEAR SKIES IN THE WHOLE REGION. NO SIGNIFICANT CHANGES TO THE
CURRENT CONDITIONS ARE EXPECTED WITHIN THE NEXT 48 TO 72 HOURS.

CARIBBEAN SEA...
THE SOUTHERN STREAM JET REMAINS ACTIVE AT THE BASE OF A BROAD
MIDDLE TO UPPER LEVEL TROUGH EXTENDING ACROSS THE CENTRAL CUBA
AND THE NW CARIBBEAN. THIS IS ALLOWING SCATTERED MID AND UPPER
CLOUDINESS ACROSS THE CENTRAL PORTION OF THE BASIN PARTICULARLY
FROM NICARAGUA TO HISPANIOLA. RIDGING N OF THE AREA IS
MAINTAINING FRESH TO STRONG TRADE WINDS ACROSS THE CENTRAL
CARIBBEAN...PARTICULARLY OFF THE COAST OF NE COLOMBIA AND NW
VENEZUELA. FRESH TRADE WINDS ARE ALSO FUNNELING ACROSS THE GULF
OF HONDURAS. LITTLE CHANGE IS EXPECTED IN THE PATTERN THROUGH
THE WEEKEND.

...HISPANIOLA...
SHOWERS AND A FEW THUNDERSTORMS WILL PERSIST ACROSS HISPANIOLA
FOR THE NEXT COUPLE OF DAYS...RELATED TO A MID TO UPPER TROUGH
EXTENDING FROM CENTRAL CUBA AND THE NW CARIBBEAN. LITTLE CHANGE
IS EXPECTED IN THE UPPER PATTERN...AND THE PERSISTENT MODERATE
TO AT TIMES HEAVY PRECIPITATION OVER HIGHER TERRAIN COULD RESULT
IN LOCALIZED FLOODING. WHILE WIDESPREAD HEAVY CONVECTION HAS NOT
BEEN NOTICED...HISPANIOLA HAS BEEN IN THIS WET PATTERN FOR THE
PAST SEVERAL DAYS. STRONGER CONVECTION IS LIKELY OVER THE N
CENTRAL MOUNTAIN RANGE BY AFTERNOON. A WEAK SURFACE TROUGH
REMAINS IN THE AREA. LOOKING AHEAD TO LATE IN THE
WEEKEND...SLIGHTLY DRIER CONDITIONS ARE EXPECTED AS THE AXIS OF
THE UPPER TROUGH SHIFT MORE TO THE EAST AND DRIER MID ATLC AIR
ENCOMPASSES THE LOWER AND MID LEVELS. DESPITE LOWER SLIGHTLY
LOWER MOISTURE...AFTERNOON CONVECTION MAY BE ENHANCED SLIGHTLY
OVER THE MOUNTAINS EARLY IN THE WEEK AS WEAK DISTURBANCES WILL
MOVE N OF THE AREA IN THE NW FLOW ALOFT.

ATLANTIC OCEAN...
RECENT ASCAT SATELLITE DATA SHOWED MODERATE TO FRESH SW FLOW
NEAR AN AREA OF SHOWERS AND THUNDERSTORMS N OF 29N BETWEEN 70W
AND 75W...AHEAD OF A SURFACE TROUGH OFF THE CAROLINA COAST. THE
TROUGH...AND A WEAK COLD FRONT BEHIND IT...ARE ASSOCIATED WITH A
SERIES OF MID/UPPER DISTURBANCES MOVING FROM THE TENNESSEE
VALLEY THROUGH THE CAROLINAS...AND TOWARD THE BASE OF A BROAD
MID/UPPER TROUGH EXTENDING ALONG ROUGHLY 75W. THE UPPER TROUGH
WILL BECOME MORE AMPLIFIED THROUGH THE WEEKEND AND SHIFT
EASTWARD SLIGHTLY AS THE WEAK DISTURBANCES MOVE THROUGH. THE
ASSOCIATED COLD FRONT WILL SAG SOUTHWARD TO 25N THROUGH SAT THEN
BECOME DIFFUSE.

A FEW SHOWERS AND THUNDERSTORMS ARE NOTED TO THE SOUTHEAST OF
THIS TROUGH N OF PUERTO RICO AND THE LEEWARD ISLANDS.

FARTHER EAST...BROAD RIDGING WILL EXTEND ACROSS
THE BASIN INTO THE N CENTRAL ATLANTIC. A PAIR OF TROPICAL WAVES
WILL MIGRATE WESTWARD SOUTH OF THE RIDGE THROUGH THE
WEEKEND...ENHANCING TRADE WIND FLOW W OF 40W.

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

$$
CHRISTENSEN


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