[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 26 2012

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
1735 UTC.

...TROPICAL WAVES...

TROPICAL WAVE AXIS MOVES ACROSS THE ERN TRPCL ATLC ANALYZED FROM
18N30W TO 10N32W. THIS SYSTEM WAS LABELED AS A LOW PRESSURE
SYSTEM ON PREVIOUS SURFACE MAPS. HOWEVER...AS THE SYSTEM MOVES
OVER UNFAVORABLE REGIONS OF DEVELOPMENT...IT'S LOW LEVEL CENTER
HAS WEAKENED EXPOSING ONLY A WAVE AXIS. THIS SCENARIO WAS
CONCLUDED THIS MORNING AS AN ASCAT SCATTEROMETER PASS WENT OVER
THIS REGION INDICATING THE ELONGATED CYCLONIC CURVATURE ALONG
THE WAVE AXIS...WHICH IS FOUND WEST OF A REGION OF DEEP LAYER OF
MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. SOME MID
LEVEL CYCLONIC CURVATURE REMAINS AROUND THE WAVE AXIS ON THE
CLOUD PATTERN ON EARLY VISIBLE SATELLITE PICTURES OF THE DAY.
THE RAIN AND THUNDERSTORM ACTIVITY REMAINS MOSTLY S OF THE WAVE
AXIS WHERE THE MONSOON TROUGH IS ANALYZED.

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
ANALYZED FROM 23N45W TO THE MONSOON TROUGH AXIS NEAR 11N48W
MOVING W AT ABOUT 5-10 KT. THE WAVE REMAINS ALONG THE WRN EDGE
OF A SURGE OF DEEP LAYER MOISTURE DEPICTED ON TOTAL PRECIPITABLE
WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN A DENSE
REGION OF SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY AROUND
THE WAVE TO NEAR ZERO.

A TROPICAL WAVE MOVES ACROSS THE N-WESTERN CARIBBEAN WITH AXIS
ANALYZED FROM THE WRN TIP OF CUBA NEAR 22N84W TO INLAND OVER
N-CENTRAL NICARAGUA NEAR 14N85W. WAVE REMAINS ON THE WRN EDGE OF
A SURGE OF DEEP MOISTURE NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY. AN UPPER LEVEL INVERTED TROUGH MOVES ACROSS CENTRAL
AMERICA AND YUCATAN PENINSULA ON WATER VAPOR IMAGERY. THIS
FEATURE ALONG WITH LOW LEVEL MOISTURE CONVERGENCE IN THE
VICINITY OF THE WAVE AXIS IS GENERATING AN AREA OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS S OF 19N W OF 82W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE TROPICAL
ATLC THROUGH THE COAST DAKAR SENEGAL TO JUST EAST OF THE ERN
ATLC TROPICAL WAVE NEAR 13N28W...RESUMING SW OF THE SAME
TROPICAL WAVE NEAR 10N32W CONTINUING WESTWARD ALONG 11N44W TO
9N52W...WHERE A SHORT SECTION OF THE ITCZ CONTINUES TO THE COAST
OF GUYANA NEAR 7N58W. CLUSTERS OF SCATTERED MODERATE TO STRONG
CONVECTION ARE FROM 6N-11N BETWEEN 50W-60W. SIMILAR CONVECTION
IS FOUND S OF ERN ATLC TROPICAL WAVE FROM 6N-11N BETWEEN
28W-38W. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS
WITHIN 170 NM OFF THE COAST OF WEST AFRICA FROM SIERRA LEONE TO
GUINEA-BISSAU.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH IS ANALYZED FROM THE NRN FLORIDA PENINSULA NEAR
30N83W TO 28N84W. DOPPLER RADAR IMAGERY SHOWS SCATTERED MODERATE
TO HEAVY SHOWERS AND THUNDERSTORMS N OF 27N E OF 89W. AN UPPER
INVERTED TROUGH BEGAN TO INTERACT WITH THE SURFACE FEATURE THIS
MORNING AND IT WILL CONTINUE TO SUPPORT THE SHOWER ACTIVITY IN
THIS REGION OVER THE NEXT 24 HOURS...AS AN UPPER TROUGH MOVING
ACROSS THE CENTRAL CONUS TAKES OVER THE ERN AND SE CONUS DURING
THE NEXT 24-48 HOURS. THIS WILL LIKELY KEEP THE CONVECTION OVER
THE NE AND N-CENTRAL GULF FAIRLY ACTIVE DURING THE FORECAST
PERIOD. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
DEPICTED ON SATELLITE IMAGERY WITHIN 80 NM OFF THE TEXAS/MEXICO
COAST FROM 24N-29N. THE ACTIVITY IS EXPECTED TO MOVE N OVER THE
NEXT 24 HOURS. A TROPICAL WAVE CURRENTLY MOVING ACROSS THE NW
CARIBBEAN WILL BEGIN TO AFFECT THE YUCATAN PENINSULA AND ERN BAY
OF CAMPECHE OVER THE WEEKEND.

CARIBBEAN SEA...
THE ONLY REGION OF ACTIVE WEATHER ACROSS THE CARIBBEAN THIS
AFTERNOON IS FOUND OVER THE NW BASIN...DUE TO THE PASSAGE OF A
TROPICAL WAVE WITH AXIS ANALYZED BETWEEN WRN CUBA AND CENTRAL
HONDURAS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE S OF
19N W OF 82W. THIS AREA OF CONVECTION WILL CONTINUE TO MOVE
INLAND OVER THE YUCATAN PENINSULA DURING THE NEXT 24 HOURS. FOR
MORE DETAILS SEE TROPICAL WAVES DISCUSSION ABOVE. VISIBLE
SATELLITE IMAGERY SHOWS THE REMAINDER OF THE DISCUSSION AREA
UNDER FAIR WEATHER CONDITIONS. THIS ENVIRONMENT IS HEAVILY
RELATED TO STRONG SUBSIDENCE AND DRY AIR ALOFT NOTED ON WATER
VAPOR IMAGERY...IN COMBINATION WITH SAHARAN DUST ALOFT NOTED ON
MOST UPPER AIR SOUNDINGS AVAILABLE ACROSS THE CARIBBEAN ISLANDS.

ATLANTIC OCEAN...
AN UPPER RIDGE COVERS THE FAR WRN ATLC ANCHORED BY A 1015 MB
HIGH N OF THE DISCUSSION AREA NEAR 35N70W. HOWEVER...AN UPPER
TROUGH IS TO THE E OF THE UPPER RIDGE...COVERING THE REMAINDER
OF THE WRN ATLC INTO THE CENTRAL ATLC SUPPORTING A COLD FRONT
THAT ENTERS THE REGION NEAR 32N62W CONTINUING WSW ALONG 29N68W
TO 30N72W WHERE IT BECOMES STATIONARY AS IT CONTINUES OUT OF THE
REGION ALONG 32N75W. THIS FRONTAL BOUNDARY IS GENERATING AN AREA
OF SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 150 NM SE OF THE
BOUNDARY E OF 70W. THE COLD FRONT AND ASSOCIATED CONVECTION IS
FORECAST TO MOVE EASTWARD BEFORE LOOSING MOMENTUM AND BECOMING
STATIONARY DURING THE NEXT 24 HOURS. OTHERWISE...BROAD UPPER
LEVEL RIDGING COVERS THE REMAINDER OF THE ATLC DISCUSSION AREA.
THE FAIR WEATHER IS FURTHER ENHANCED BY SAHARAN DUST COVERING
THE ENTIRE ATLC DISCUSSION AREA.

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

$$

GARCIA




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