[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211048
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1000 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS FROM 20N50W TO 10N54W
MOVING W-NW NEAR 10 KT. THE WAVE IS EMBEDDED WITHIN A MODERATE
MOIST ENVIRONMENT AS DEPICTED IN TOTAL PRECIPITABLE WATER
IMAGERY. THE METEOSAT-9 SAL TRACKING PRODUCT SHOWS SOME DRY AIR
SURROUNDING AND SPREADING OVER THE WAVE ENVIRONMENT WHICH IS
HINDERING DEEP CONVECTION.

THE TROPICAL WAVE FORMERLY MOVING ACROSS CENTRAL AMERICA HAS
BEEN ABSORBED BY A 1011 MB LOW LOCATED JUST NORTH OF THE CHIVELA
PASS MEXICO. SCATTERED MODERATE CONVECTION WITH EMBEDDED
THUNDERSTORMS ARE OVER SOUTHERN MEXICO EXTENDING TO THE BAY OF
CAMPECHE S OF 20N. REMNANTS SHOWERS FROM THE WAVE LINGERS OVER
WESTERN HONDURAS AND EL SALVADOR.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 16N16W AND CONTINUES ALONG 07N26W TO 04N38W.
THE ITCZ AXIS EXTENDS FROM 04N38W TO 03N45W 01N50W. NUMEROUS
MODERATE CONVECTION WITH ISOLATED THUNDERSTORMS IS FROM 07N-15N
E OF 22W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF THE
MONSOON TROUGH AXIS BETWEEN 22W AND 27W. ISOLATED SHOWERS ARE
WITHIN 70 NM EITHER SIDE OF THE AXIS BETWEEN 28W AND 44W.

...DISCUSSION...

GULF OF MEXICO...
A MODERATE MOIST ENVIRONMENT IS ACROSS THE BASIN IN THE MIDDLE
AND LOWER LEVELS AS DEPICTED IN TOTAL PRECIPITABLE WATER AND
WATER VAPOR IMAGERY. SE WIND FLOW IN THE RANGE OF 5-15 KT
CONTINUES TO COVER MOST OF THE GULF THIS MORNING. THESE WINDS
ARE BANKING LOW LEVEL CLOUDS ALONG THE NW GULF COASTLINES
BETWEEN 91W AND 96W. MIDDLE TO UPPER LEVEL DIVERGENCE IN THE
SAME AREA IS SUPPORTING RAINSHOWERS AND THUNDERSTORMS N OF 27N
FROM MORGAN CITY LOUISIANA TO FREEPORT TEXAS. A TROPICAL WAVE
FORMERLY MOVING ACROSS CENTRAL AMERICA HAS BEEN ABSORBED BY THE
1011 MB LOW LOCATED JUST NORTH OF THE CHIVELA PASS MEXICO.
SCATTERED MODERATE CONVECTION WITH EMBEDDED THUNDERSTORMS ARE
OVER SOUTHERN MEXICO ASSOCIATED WITH THIS LOW AND EXTENDS TO THE
BAY OF CAMPECHE S OF 20N.

SURFACE RIDGING AND RETURN FLOW WILL PREVAIL ACROSS THE GULF
DURING THE NEXT 48 HOURS. FAIR WEATHER IS EXPECTED FOR THE MOST
PART DURING THIS TIME BEING SUPPORTED BY DRY AIR ADVECTION FROM
THE WESTERN CARIBBEAN.

CARIBBEAN SEA...
EXCEPT FOR THE FAR WESTERN CARIBBEAN W OF 86W AND THE SOUTHERN
CARIBBEAN S OF 13N...DRY AIR SPREADS ACROSS THE BASIN IN THE
MIDDLE AND LOWER LEVELS AS DEPICTED IN TOTAL PRECIPITABLE WATER
AND WATER VAPOR IMAGERY WHICH IS SUPPORTING FAIR WEATHER.
NUMEROUS MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED
THUNDERSTORMS ARE OVER THE SOUTHERN CARIBBEAN S OF 13N WITHIN
120 NM OF THE COASTS OF NICARAGUA AND COSTA RICA AS WELL AS
WITHIN 100 NM N OF THE PANAMA COASTLINE. THIS CONVECTION IS
ASSOCIATED WITH THE MONSOON TROUGH WHICH AXIS MOVES ACROSS COSTA
RICA AND PANAMA TO A 1008 MB LOW OVER NORTHERN COLOMBIA.
OTHERWISE...A TIGHT PRESSURE GRADIENT OVER THE CENTRAL CARIBBEAN
CONTINUES TO SUPPORT GALE FORCE WINDS FROM 12N TO 14N BETWEEN
73W AND 76W THAT ARE EXPECTED TO SUBSIDE SUNDAY AFTERNOON.
TRADEWINDS OF 15-20 KT ARE OVER THE REST OF THE BASIN.

EXCEPT FOR THE SOUTHERN CARIBBEAN...FAIR WEATHER IS EXPECTED
OVER MOST OF THE CARIBBEAN UNTIL LATE SUNDAY WHEN CONDITIONS
START TO DEGRADE AS A TROPICAL WAVE ENTERS THE EASTERN
CARIBBEAN. THE WAVE IS EXPECTED TO MOVE ACROSS PUERTO RICO
MONDAY AFTERNOON AND OVER THE HISPANIOLA EARLY TUESDAY.

HISPANIOLA...
DRY AIR CONTINUES ACROSS LA HISPANIOLA THIS MORNING WHICH IS
LIMITING ANY CONVECTIVE ACTIVITY. HOWEVER IN THE AFTERNOON/EARLY
EVENING RAINSHOWERS ASSOCIATED WITH DIURNAL SURFACE HEATING AND
ENHANCED BY AN UPPER LEVEL LOW OVER THE W ATLC EXTENDING A
TROUGH TO THE ISLAND CAN BE EXPECTED. WEATHER CONDITIONS IMPROVE
MONDAY MORNING AS A DRY AIR MASS MOVES ACROSS THE ISLAND BUT
START TO DETERIORATE AGAIN IN THE AFTERNOON AS THE TROPICAL WAVE
MOVES WESTWARD ACROSS PUERTO RICO. THE TROPICAL WAVE IS EXPECTED
TO ENTER THE DOMINICAN REPUBLIC EARLY TUESDAY AND RAINSHOWERS
ARE EXPECTED ACROSS THE ENTIRE ISLAND AS THE WAVE DRIFTS
WESTWARD.

ATLANTIC OCEAN...
MODERATE MOISTURE AND MIDDLE LEVEL DIVERGENCE IS OVER THE
WESTERN ATLC ENHANCING NUMEROUS MODERATE CONVECTION N OF THE
BAHAMAS BETWEEN 77W AND 80W. SURFACE RIDGING IS ACROSS THE
REMAINDER BASIN ANCHORED BY A 1022 MB HIGH NEAR 28N66W AND
ANOTHER 1022 MB HIGH FURTHER EAST NEAR 28N39W. BESIDES THE
REGIONS FORMERLY MENTIONED...FAIR WEATHER IS ACROSS THE ATLC
SUPPORTED BY DRY AIR AT THE LOWER LEVELS.

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

$$
RAMOS


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