Tropical Weather Discussion
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000
AXNT20 KNHC 190005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAY 18 2015

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
2345 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL
ATLANTIC NEAR 09N13W CONTINUING TO 05N21W. THE ITCZ BEGINS NEAR
05N21W AND CONTINUES ALONG 03N40W TO THE NORTHERN COAST OF
BRAZIL NEAR 01N50W. SCATTERED MODERATE CONVECTION IS FROM 01N TO
12N E OF 25W AND FROM 01N TO 05N BETWEEN 33W AND 43W.

...DISCUSSION...

GULF OF MEXICO...

A SURFACE RIDGE EXTENDS FROM THE NORTHERN PLAINS SE TO THE SE
CONUS INTO THE N-NE GULF AND THE SW N ATLC WATERS. IN THE GULF
THE RIDGE IS BEING ANCHORED BY A 1021 MB HIGH NEAR 29N84W AND
PROVIDES E-SE WIND FLOW OF 10 TO 15 KT...EXCEPT IN THE VICINITY
OF THE HIGH PRESSURE CENTER WHERE WINDS ARE LESS THAN 10 KT AND
VARIABLE. MIDDLE TO UPPER LEVEL RIDGING DOMINATES ACROSS THE
BASIN ALONG WITH DRY AIR...THUS SUPPORTING FAIR WEATHER.
ISOLATED SHOWERS ARE OVER THE SOUTH-CENTRAL...SOUTHWEST FLORIDA
AND ADJACENT WATERS BEING ENHANCED BY SHALLOW MOISTURE AND
SURFACE TROUGHING. FOG IS BEING REPORTED OVER THE NW BASIN N OF
27N W OF 93W COINCIDING WITH MEDIUM PROBABILITIES OF FOG IN THE
GOES-13 IFR IMAGERY. SURFACE RIDGING AND FAIR WEATHER CONDITIONS
WILL CONTINUE DURING THE NEXT THREE DAYS.

CARIBBEAN SEA...

SOUTHWESTERLY TO WESTERLY FLOW DOMINATES ALOFT AND ADVECTS
MOISTURE FROM AREAS OF LOW PRESSURE OVER THE EPAC
WATERS...COLOMBIA AND VENEZUELA. SSMI TPW IMAGERY SHOW MOISTURE
DOMINATING ALSO AT THE LOWER LEVELS...WHICH ENHANCES ISOLATED
SHOWERS AND TSTMS OVER EASTERN
CUBA...HISPANIOLA...JAMAICA...PUERTO RICO AND THE SW CARIBBEAN.
SIMILAR CONVECTION IS OBSERVED OVER THE YUCATAN CHANNEL. MIDDLE-
LEVEL TROUGHING MOVING EASTWARD ALONG WITH LOW LEVEL MOISTURE
WILL CONTINUE TO ENHANCE SHOWERS FOR THE SAME REGIONS DURING THE
NEXT TWO DAYS.

...HISPANIOLA...

LINGERING MOISTURE ASSOCIATED WITH THE PASSAGE OF A STATIONARY
FRONT N OF THE ISLAND ALONG WITH MIDDLE-LEVEL TROUGHING SUPPORT
SCATTERED SHOWERS AND TSTMS OVER THE CENTRAL ISLAND AND ISOLATED
SHOWERS ELSEWHERE. THIS SHOWER ACTIVITY IS FORECAST TO PERSIST
DURING THE NEXT TWO DAYS.

ATLANTIC OCEAN...

A SURFACE RIDGE EXTENDS FROM THE NORTHERN PLAINS SE TO THE SE
CONUS INTO THE N-NE GULF AND THE SW N ATLC WATERS. IN THE SW N
ATLC THE RIDGE IS BEING ANCHORED BY A 1022 MB HIGH NEAR 30N75W.
A WEAKNESS IN THE RIDGE IS BEING ANALYZED AS A SURFACE TROUGH
ALONG THE NORTHERN BAHAMAS...ENHANCING SHOWERS THERE AND IN
ADJACENT WATERS. A MIDDLE TO UPPER LEVEL LOW OVER THE NORTH-
CENTRAL ATLC EXTENDS A TROUGH SOUTHWARD THAT CONTINUES TO
SUPPORT A COLD FRONT N OF 30N AND A STATIONARY FRONT ALONG
30N44W SW TO 22N57W TO 19N66W. ISOLATED SHOWERS ARE WITHIN 100
NM EITHER SIDE OF THE BOUNDARY. ELSEWHERE...RIDGING AND FAIR
WEATHER DOMINATES. THE FRONT WILL WEAKEN TUESDAY MORNING LEAVING
AN ELONGATED AREA OF LOW PRESSURE OVER THE CENTRAL ATLC. A NEW
COLD FRONT ENTERS THE NORTHERN-CENTRAL BASIN WEDNESDAY MORNING.

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

$$
NR



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