[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 060602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUL 06 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
0445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 19N34W TO 9N34W MOVING WEST NEAR 15 KT.
THE WAVE IS EMBEDDED WITHIN AN AREA OF SLIGHTLY INCREASED
MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY.
HOWEVER...A LARGE SAHARAN AIR LAYER SURROUNDS THE WAVE...WHICH
IS INHIBITING ANY DEEP CONVECTION NEAR THE AXIS. AN AREA OF
CONVECTION IS EMBEDDED WITHIN THE MONSOON TROUGH NEAR A SURFACE
LOW TO THE EAST THAT MAY BE ASSOCIATED WITH THE WAVE. THE LOW
WILL BE DISCUSSED WITHIN THE ITCZ/MONSOON TROUGH SECTION.

TROPICAL WAVE IS ALONG 20N46W TO 12N56W. THE LOCATION OF THIS
WAVE HAS ESSENTIALLY STAYED STATIONARY OVER THE PAST 24 HOURS.
HOWEVER...FROM LOOKING AT MODEL POTENTIAL VORTICITY FIELDS THE
WAVE IS LIKELY FARTHER WEST NEAR THE LESSER ANTILLES WHERE A
SURFACE TROUGH IS ANALYZED. THIS WAVE WILL LIKELY BE RELOCATED
ON THE NEXT ANALYSIS. IN ITS CURRENT LOCATION...A BROAD MOISTURE
SIGNAL IS PRESENT NEAR THE WAVE. ISOLATED MODERATE CONVECTION IS
FROM 13N-17N BETWEEN 46W-49W...AND FROM 16N-18N BETWEEN 53W-56W.

TROPICAL WAVE IS ALONG 18N84W TO 9N81W MOVING WEST INTO CENTRAL
AMERICA 15-20 KT. ONLY A WEAK MOISTURE SIGNAL IS EVIDENT NEAR
THE WAVE WITH MUCH HIGHER MOISTURE CONTENT TO THE NORTH OVER THE
NW CARIBBEAN. ONLY A SMALL AREA OF MODERATE CONVECTION IS NEAR
THE WAVE FROM 10N-11N BETWEEN 82W-84W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF MAURITANIA NEAR
19N16W TO A 1012 MB SURFACE LOW NEAR 8N28W TO 7N35W. THE ITCZ
BEGINS NEAR 7N35W AND CONTINUES ALONG 6N44W 3N51W. SCATTERED
MODERATE/STRONG CONVECTION IS WEST OF THE SURFACE LOW CENTER
FROM 5N-9N BETWEEN 29W-33W. SIMILAR ACTIVITY IS FROM 4N-7N
BETWEEN 42W-47W...AND FROM 2N-6N BETWEEN 48W-53W.

...DISCUSSION...

GULF OF MEXICO...
MOIST CONDITIONS REMAIN ACROSS MUCH OF THE GULF OF MEXICO. THIS
IS DUE TO A COMBINATION OF MOIST SOUTHERLY TO SOUTHEASTERLY FLOW
AT THE SURFACE THROUGHOUT MUCH OF THE AREA...AND MOIST
SOUTHWESTERLY AND DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL
TROUGH OVER THE CENTRAL CONUS THAT IS PUSHING INTO THE NW
GULF...AND AN UPPER LEVEL RIDGE OVER THE REMAINDER OF THE BASIN
EXTENDING FROM THE BAY OF CAMPECHE NEAR 20N96W TO 31N84W.
ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS ARE THROUGHOUT THE
AREA EXCEPT FOR THE NW CORNER WHERE SKIES ARE CLEAR. MORE
SCATTERED ACTIVITY IS FROM 22N-27N BETWEEN 89W-91W NEAR THE AREA
OF STRONGEST DIFFLUENCE ALOFT. SCATTERED ACTIVITY IS ALSO
THROUGHOUT THE STRAITS OF FLORIDA. A SURFACE TROUGH IS ANALYZED
IN THE FAR WESTERN GULF ALONG 27N94W TO 20N96W CONTRIBUTING TO
SOME OF THE ACTIVITY. THE SURFACE TROUGH IS EXPECTED TO DRIFT
WEST AND NORTH OVER THE NEXT 24 HOURS WHILE MOIST CONDITIONS
WILL CONTINUE TO IMPACT THE BASIN FOR AT LEAST THE NEXT DAY OR
SO.

CARIBBEAN SEA...
MOISTURE FROM THE GULF OF MEXICO IS DRAWN OVER THE NW CARIBBEAN
IN NORTHERLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE OVER THE
GULF. ONLY A SMALL AREA OF SCATTERED SHOWERS/THUNDERSTORMS IS
NEAR CENTRAL CUBA FROM 20N-23N BETWEEN 78W-81W. A FEW POSSIBLE
ISOLATED SHOWERS ARE OVER THE REMAINDER OF WESTERN CUBA AND THE
WATERS TO THE SOUTH. A TROPICAL WAVE IS MOVING INTO CENTRAL
AMERICA...BUT DRY AIR IS LIMITING ANY ACTIVITY NEAR THE AXIS.
THE REMAINDER OF THE BASIN IS FAIRLY DRY AS WELL WITH A FEW
ISOLATED SHOWERS OVER THE NE CARIBBEAN NEAR A SURFACE TROUGH
ANALYZED ALONG 22N58W TO 12N66W. THIS SURFACE TROUGH IS MORE
LIKELY A TROPICAL WAVE THAT IS CURRENTLY ANALYZED FARTHER EAST.
FROM THE CURRENT ANALYSIS THE TROPICAL WAVE APPEARS TO NOT HAVE
MOVED MUCH IN THE LAST 24 HOURS...BUT IT LIKELY HAS MOVED AND
WILL BE RELOCATED NEAR THE EASTERN CARIBBEAN ON THE NEXT
ANALYSIS. ALOFT...A NARROW UPPER TROUGH EXTENDS FROM HAITI TO
PANAMA...BUT IS ACCOMPANIED BY DRY AIR ALOFT. UPPER LEVEL
RIDGING COVERS THE REMAINDER OF THE BASIN ALSO ACCOMPANIED BY
DRY AIR ALOFT. THE WAVE MOVING INTO CENTRAL AMERICA IS EXPECTED
TO DISSIPATE OVER THE NEXT 24 HOURS...WHILE THE WAVE THAT WILL
BE ANALYZED NEAR THE EASTERN CARIBBEAN WILL CONTINUE WESTWARD TO
WEST-NORTHWESTWARD.

HISPANIOLA...
SHOWERS THAT WERE IMPACTING WESTERN HAITI ARE NOW MOSTLY
DISSIPATED LEAVING THE ISLAND MOSTLY DRY AT THIS TIME. DRY AIR
WILL CONTINUE TO KEEP CONDITIONS FAIR EXCEPT DURING PEAK DAYTIME
HEATING WHERE CONVECTION IS POSSIBLE. AN AREA OF MOISTURE OVER
THE FAR EASTERN CARIBBEAN IS EXPECTED TO REACH HISPANIOLA BY
SUNDAY MORNING...WHICH WILL INCREASE THE CHANCE OF PRECIPITATION
FOR SEVERAL DAYS AFTER.

ATLANTIC OCEAN...
BROAD SURFACE RIDGING DOMINATES THE WEST ATLC AROUND A 1028 MB
HIGH NEAR 34N71W. THE RIDGE IS SUPPORTED BY BROAD UPPER RIDGING
CENTERED NEAR 36N68W. HOWEVER...A NARROW UPPER TROUGH ALONG 80W
IS SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS NEAR THE STRAITS OF
FLORIDA FROM 23N-26N WEST OF 79W. AN UPPER LEVEL LOW IS CENTERED
NEAR 23N64W SUPPORTING A FEW ISOLATED SHOWERS FROM 22N-24N
BETWEEN 62W-66W. A SURFACE TROUGH IS TO THE EAST ALSO SUPPORTING
ISOLATED SHOWERS FROM 17N-23N BETWEEN 57W-63W. A DISSIPATING
COLD FRONT TO THE NORTH EXTENDS INTO THE AREA ALONG 31N45W TO
30N52W SUPPORTING SCATTERED SHOWERS WITHIN 45 NM EITHER SIDE.
THE REMAINDER OF THE BASIN IS DOMINATED BY BROAD SURFACE
RIDGING. BROAD UPPER RIDGING COVERS THE TROPICAL ATLC CENTERED
NEAR 12N56W. AN UPPER TROUGH IS TO THE NORTH SUPPORTING THE
FRONTAL BOUNDARY. VERY DRY AIR IS THROUGHOUT THE EAST ATLC DUE
TO THE PRESENCE OF A BROAD SAHARAN AIR LAYER.

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

$$
WALTON

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