[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAY 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC.

...TROPICAL WAVE...
TROPICAL WAVE EXTENDS FROM 15N50W TO 3N51W MOVING W-NW NEAR 15
KT OVER THE PAST 24 HOURS. TOTAL PRECIPITABLE WATER IMAGERY
INDICATE A SLIGHT MOISTURE REDUCTION WITHIN THE WAVE ENVIRONMENT
WHILE MODEL GUIDANCE SHOW A WEAK SIGNAL AT 700 MB. STRONG DEEP
LAYER WESTERLY SHEAR IS LIMITING THE CONVECTIVE ACTIVITY TO
SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS
WITH ACTIVITY CONCENTRATED ALONG THE COAST OF FRENCH GUIANA.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 14N17W
INTO THE TROPICAL ATLC THROUGH 5N25W TO 2N34W. THE ITCZ AXIS
BEGINS NEAR 2N34W AND CONTINUES TO 3N47W. SCATTERED MODERATE
ISOLATED STRONG CONVECTION WAS NOTED FROM 1N-6N BETWEEN 15W-26W.
A 1010 MB LOW IS S OF THE EQUATOR NEAR 4S30W. CONVECTION
ASSOCIATED WITH THE LOW...A CLUSTER OF MODERATE CONVECTION WAS
WITHIN 75 NM OF THE LOW.

...DISCUSSION...

GULF OF MEXICO...
A BROAD VERY DEEP MID-TO UPPER LEVEL TROUGH FOR MID-MAY IS OVER
THE EASTERN U.S. WITH THE BASE OF THE TROUGH EXTENDING ACROSS
MUCH OF THE GULF. THERE WAS A REINFORCING SHORTWAVE TROUGH
EXTENDING FROM THE TENNESSEE RIVER VALLEY TO SE TEXAS. A THIN
RIBBON OF VERY DRY AIR ALOFT COVERED THE GULF FROM 24N-27N. AT
THE SURFACE...A BROAD RIDGE IS OVER THE BASIN WHICH WAS ANCHORED
BY A PAIR OF 1023 MB HIGH PRESSURE CENTERS OVER THE FLORIDA
PANHANDLE AND OFF THE GEORGIA COAST. SSMI AND TPW IMAGERY
VALIDATED THE RIBBON OF DRY AIR OVER THE BASIN WHICH WAS
REFLECTED IN CLEAR SKIES WITH PATCHES OF SCATTERED STRATO-
CUMULUS CLOUDS IN VISIBLE SATELLITE IMAGERY. THE ONLY EXCEPTION
TO THE GENERAL CONDITIONS WERE SCATTERED SHOWERS OVER THE
YUCATAN CHANNEL ASSOCIATED WITH THE TAIL END OF A DISSIPATING
STATIONARY FRONT OVER THE NW CARIBBEAN. SATELLITE DERIVED WINDS
SHOW THE SURFACE RIDGE IS PROVIDING ANTICYCLONIC FLOW OF 10-20
KT OVER THE GULF WITH THE STRONGEST WINDS NOTED OVER THE SE
BASIN S OF 24N BETWEEN 83W-87W. THE HIGH PRESSURE CENTER WILL
SHIFT NE TOWARD NORTHERN FLORIDA WHERE IT IS EXPECTED TO
DISSIPATE THIS AFTERNOON. SURFACE RIDGING WILL CONTINUE THROUGH
TUESDAY NIGHT. FAIR WEATHER IS EXPECTED THROUGHOUT THE PERIOD.

CARIBBEAN SEA...
THE TROUGH ALOFT OVER THE EASTERN U.S. EXTENDS INTO THE WESTERN
ATLC TO SUPPORT A COLD FRONT THAT TRANSITIONS INTO A STATIONARY
FRONT NEAR 27N73W EXTENDING SW TO CENTRAL CUBA NEAR 22N79W TO
THE EXTREME NE CORNER OF THE YUCATAN PENINSULA NEAR CANCUN. A
BROAD MID-TO UPPER LEVEL RIDGE ANCHORED BY AN ANTICYCLONE NEAR
COSTA RICA COVERED NEARLY THE ENTIRE CARIBBEAN BASIN. UPPER
LEVEL DIFFLUENT FLOW BETWEEN THE ANTICYCLONE AND THE
AFOREMENTIONED TROUGH OVER THE GULF OF MEXICO WAS PROVIDING
SUPPORT FOR SCATTERED SHOWERS AND ISOLATED TSTMS ALONG AND TO
THE SOUTH OF THE DISSIPATING STATIONARY FRONT...GENERALLY N OF
19N W OF 78W. MOISTURE ASSOCIATED WITH THE FRONTAL BOUNDARY IS
BEING ADVECTED TO HISPANIOLA WHICH IS SUPPORTING CLOUDINESS AND
ISOLATED SHOWERS ACROSS THE ISLAND. DEEP LAYER DRY AIR ACROSS
THE REMAINDER BASIN SUPPORTS FAIR WEATHER...EXCEPT FOR THE
LESSER ANTILLES WHERE A MOIST AIRMASS IS ENHANCING RAINSHOWERS.
SCATTEROMETER DATA SHOW TRADES OF 10-15 KT ACROSS THE BASIN
EXCEPT WITHIN 100 NM OF NORTHERN COLOMBIA COASTLINE WHERE WINDS
REACH A MAXIMUM OF 20 KT. THE PORTION OF THE FRONT OVER THE NW
BASIN IS EXPECTED TO DISSIPATE BY TUESDAY MORNING. SHOWERS ARE
FORECAST FOR CUBA AND HISPANIOLA THROUGH THIS PERIOD. MODERATE
TO FRESH TRADE WINDS WILL PREVAIL ACROSS THE REGION.

...HISPANIOLA...
MOISTURE ASSOCIATED WITH A FRONTAL BOUNDARY EXTENDING FROM THE
SW N ATLC INTO THE NW CARIBBEAN IS BEING ADVECTED TO HISPANIOLA
WHICH IS SUPPORTING CLOUDINESS AND DEVELOPING SCATTERED SHOWERS
OVER THE INTERIOR OF THE ISLAND. DEEP LAYERED MOISTURE WILL
REMAIN IN THE VICINITY OF THE ISLAND THROUGH MID WEEK KEEPING
AFTERNOON SHOWERS/THUNDERSTORMS OVER THE ISLAND.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH OVER THE EASTERN U.S. EXTENDS
INTO THE FAR WESTERN ATLC TO SUPPORT A COLD FRONT ANALYZED FROM
32N69W EXTENDING SW TO 27N73W WHERE IT TRANSITIONS INTO A
STATIONARY FRONT TO CENTRAL CUBA NEAR 22N79W. MOST OF THE
CONVECTIVE PRECIPITATION ASSOCIATED WITH THE FRONT WAS S OF 23N
EXTENDING INTO THE NW CARIBBEAN. BROKEN TO OVERCAST LOW CLOUDS
DEFINED THE FRONT N OF 23N WHERE POSSIBLE ISOLATED SHOWERS
WERE NOTED.

A LARGE DEEP LAYERED MID-TO UPPER LEVEL LOW OVER THE NORTH-
CENTRAL ATLC NEAR 37N52W SUPPORTS A 997 MB SURFACE LOW NEAR
36N51W. SEVERAL SURFACE TROUGHS WERE ROTATING AROUND THE LOW N
OF 26N BETWEEN 45W-58W. OTHERWISE...A PLUME OF BROKEN TO
OVERCAST MID AND HIGH CLOUDS WERE NOTED FROM 15N-30N BETWEEN 30W-
45W. SURFACE RIDGING DOMINATES ELSEWHERE IN THE EASTERN ATLC. W
ATLC COLD FRONT WILL SLOWLY MOVE E THROUGH TUE WHILE THE
STATIONARY FRONT GRADUALLY DISSIPATES. HIGH PRESSURE WILL BUILD
ALONG THE MID-ATLANTIC COAST SUN THROUGH MON AND SHIFT S TO OFF
THE NE FLORIDA COAST TUE.

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

$$
COBB


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