[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0539 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS FROM 19N49W TO 09N51W
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 IS SHOWING SOME DRY
AIR SPREADING OVER THE WAVE ENVIRONMENT WHICH IS HINDERING
CONVECTION.

TROPICAL WAVE MOVING ACROSS CENTRAL AMERICA WITH AXIS EXTENDING
FROM 17N86W IN THE WESTERN CARIBBEAN TO 09N86W IN THE EAST
PACIFIC. ITS AXIS IS MOVING NEAR 5 KT AND IS MOSTLY EMBEDDED IN
A MODERATE MOIST ENVIRONMENT. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS OCCURRING OVER NICARAGUA...WESTERN
HONDURAS...EASTERN GUATEMALA AND EL SALVADOR WITH ISOLATED
SHOWERS EXTENDING OVER THE  W CARIBBEAN W OF 84W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 16N16W AND CONTINUES ALONG 09N25W TO 04N38W. THE ITCZ
AXIS EXTENDS FROM 04N39W TO 03N46W 03N53W. CLUSTERS OF MODERATE
CONVECTION WITH EMBEDDED THUNDERSTORMS ARE FROM 08N-16N E OF
20W. ISOLATED MODERATE CONVECTION IS WITHIN 170 NM EITHER SIDE
OF THE AXES BETWEEN 20W AND 48W.

...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. S-SE WIND FLOW IN THE RANGE OF 5-15 KT
COVERS MOST OF THE GULF THIS EVENING. IN THE UPPER LEVELS...A
LOW OVER NE LOUISIANA EXTENDS A TROUGH TO THE BAY OF CAMPECHE
AND SOUTHERN MEXICO WHICH IS SUPPORTING A 1011 MB LOW NEAR THE
CHIVELA PASS MEXICO. CLUSTERS OF MODERATE CONVECTION WITH
EMBEDDED THUNDERSTORMS ARE OVER INLAND SOUTHERN MEXICO AND
EXTEND TO THE BAY OF CAMPECHE S OF 20N. OVER THE NE GULF...N OF
28N E OF 89W WINDS FROM THE SW ARE BANKING LOW LEVELS CLOUDS TO
NORTHERN FLORIDA. MIDDLE LEVEL DIFFLUENCE OVER THIS REGION IS
SUPPORTING A CLUSTER OF MODERATE CONVECTION N OF 28N E OF 85W.

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 85W 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. THE
AXIS OF A TROPICAL WAVE EXTENDS FROM 17N86W IN THE WESTERN
CARIBBEAN TO 09N86W IN THE EAST PACIFIC. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS OCCURRING OVER
NICARAGUA...WESTERN HONDURAS...EASTERN GUATEMALA AND EL SALVADOR
WITH ISOLATED SHOWERS EXTENDING OVER THE  W CARIBBEAN W OF 84W.
CLUSTERS OF MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED
THUNDERSTORMS ARE OVER THE SOUTHERN CARIBBEAN S OF 11N
ASSOCIATED WITH THE MONSOON TROUGH WHICH AXIS MOVES ACROSS COSTA
RICA AND PANAMA. ALSO IN THE SOUTHERN CARIBBEAN...CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE CROSSING CENTRAL AMERICA
EXTENDS WITHIN 140 NM OF THE COAST OF NICARAGUA. SCATTERED
SHOWERS EXTENDS WITHIN 70 NM N OF THE COASTS OF COLOMBIA AND
VENEZUELA BETWEEN 69W-73W ASSOCIATED WITH A 1008 MB LOW OVER
INLAND N COLOMBIA. OTHERWISE...A TIGHT PRESSURE GRADIENT OVER
THE CENTRAL CARIBBEAN HAS PRODUCED 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.

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 ON
EARLY ON TUESDAY.

HISPANIOLA...
DRY AIR IS ACROSS LA HISPANIOLA THIS EVENING LIMITING ANY
CONVECTIVE ACTIVITY. AFTERNOON/EARLY EVENING RAINSHOWERS
ASSOCIATED WITH DIURNAL SURFACE HEATING AND ENHANCED BY AN UPPER
LEVEL LOW EXTENDING A TROUGH TO THE ISLAND CAN BE EXPECTED ON
SUNDAY. WEATHER CONDITIONS IMPROVE FOR MOST OF THE DAY ON MONDAY
AS A DRY AIR MASS MOVES ACROSS THE ISLAND BUT START TO
DETERIORATE AGAIN AT NIGHT 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.

ATLANTIC OCEAN...
MODERATE MOISTURE AND MIDDLE LEVELS DIVERGENCE IS OVER THE
WESTER ATLC ENHANCING SCATTERED MODERATE CONVECTION N OF THE
BAHAMAS W OF 75W. SURFACE RIDGING IS ACROSS THE REMAINDER BASIN
ANCHORED BY A 1023 MB HIGH NEAR 28N64W AND A 1023 MB HIGH NEAR
28N35W. 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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