[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 07 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
1745 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLC EXTENDS IN A NW
TO SE FASHION FROM 23N49W TO NEAR 14N48W MOVING W AT 17 KT.
MOISTURE IS VERY LIMITED WITH THIS WAVE AS IT TRAVERSES A VERY
STABLE AND DRY ENVIRONMENT MARKED BY THE EASTERN MOST PERIPHERY
OF SAHARAN DUST. SATELLITE IMAGERY FROM DURING THE DAY SHOWS A
SMALL POCKET OF LOW TO MID LEVEL MOISTURE WITH SCATTERED SHOWERS
AND ISOLATED TSTMS WITHIN 120-180 NM W OF THE WAVE FROM 18N-23N.
LATEST TPW ANIMATION IMAGERY FAINTLY DEPICTS THIS AREA OF
MOISTURE WITH
THE WAVE.

TROPICAL WAVE IS ADVANCING ACROSS THE THE WRN CARIBBEAN SEA
STRETCHING FROM WRN CUBA SW TO GULF OF HONDURAS MOVING W NEAR 17
KT...BASED ON 24 HR EXTRAPOLATED MOTION. THE NORTHERN PORTION OF
THIS WAVE HAS DISLODGE FROM IT...AND IS NOW A SURFACE TO LOW
LEVEL TROUGH THAT EXTENDS FROM NW CUBA NE TO THE STRAITS OF
FLORIDA AND JUST TO THE SE OF S FLORIDA WHERE A WEAK SURFACE TO
LOW LEVEL CYCLONIC SWIRL WAS EARLIER NOTED. SCATTERED SHOWERS
AND TSTMS ARE QUICKLY DEVELOPING ALONG AND TO THE W OF THIS
FEATURE. THE REMAINDER OF THE WAVE REMAINS EMBEDDED IN A LARGE
SURGE OF DEEP LAYER MOISTURE COVERING THE WRN PORTION OF THE SEA
W OF 80W. TPW ANIMATION VIVIDLY DISPLAYS THIS BULGE OF
MOISTURE...AND SATELLITE IMAGERY SHOWS NUMEROUS SHOWERS AND
TSTMS CONFINED TO SW OF A LINE FROM 21N86W TO 15N81W TO 11N79W.
EXPECT THIS ACTIVITY TO BRING PERIODS OF HEAVY RAINFALL TO
EASTERN YUCATAN PENINSULA...BELIZE...HONDURAS AND NICARAGUA
TONIGHT THEN OVER THE REMAINDER OF THESE LOCATIONS SUN THROUGH
MON NIGHT.

VISIBLE SATELLITE IMAGERY FROM THE DAY REVEAL MOISTURE
CONCENTRATION IN THE SW MONSOONAL FLOW INTO FAR WRN AFRICA.
MODEL GUIDANCE FIELDS AT 700 MB ALONG WITH POTENTIAL VORTICITY
GUIDANCE SUGGEST THAT THE NEXT WAVE TO MOVE OFF THE COAST OF
AFRICA SHOULD OCCUR WITHIN THE NEXT 24-36 HRS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS SW FROM THE W COAST OF AFRICA AT COAST
OF GUINEA BISSAU NEAR 13N16W...AND EXTENDS SW TO A 1012 MB LOW
AT 10N23N AND TO 8N28W...WHERE SCATTEROMETER DATA FROM THIS
MORNING SUGGEST THE ITCZ BEGINS AND EXTENDS TO ANOTHER 1012 MB
LOW AT 7N40W AND TO THE COAST OF S AMERICA AT 7N58W. SCATTERED
STRONG CONVECTION IS JUST INLAND THE COAST OF GUINEA BISSAU.
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE MONSOON
TROUGH BETWEEN 21W-25W...AND IS ALSO RELATED TO THE 1012 MB LOW.
OTHERWISE...SCATTERED ISOLATED MODERATE CONVECTION IS ELSEWHERE
WITHIN ABOUT 60 NM EITHER SIDE OF THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...
A BROAD AREA OF UPPER LEVEL RIDGING COVERS THE ERN CONUS WITH
ITS S AND SW PERIPHERY EXTENDING SW OVER THE NRN AND CENTRAL
GULF. FAST UPPER LEVEL ELY FLOW ACROSS THESE PORTIONS OF THE
GULF DUE TO THE FLOW PATTERN SET UP BETWEEN THE HIGH AND AN
ELONGATED UPPER LOW OVER THE SE GULF IS STEERING TSTM ACTIVITY
ASSOCIATED WITH MESOSCALE OUTFLOW BOUNDARIES OVER THE FAR NRN
N OF 28N AND BETWEEN 88W AND 93W WWD TOWARDS THE NE TEXAS
AND SW LOUISIANA REGIONS. A WEAK 1019 MB SURFACE HIGH IS IN THE
NE GULF AT 28N84W WITH A RIDGE WSW TO CENTRAL TEXAS. ONLY
SCATTERED LOW CLOUDS WITH ISOLATED SHOWERS AND TSTMS ARE
NOTED ELSEWHERE ACROSS THE GULF. SCATTERED SHOWERS AND TSTMS
ARE MOVING W ACROSS THE STRAITS OF FLORIDA...AND ENTERING THE
FAR SE GULF WATERS IN ASSOCIATION WITH THE SURFACE TO LOW
LEVEL TROUGH MENTIONED ABOVE UNDER TROPICAL WAVES. WEAK SURFACE
RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN THROUGH THE
WEEKEND.

CARIBBEAN SEA...
ASIDE FROM CONVECTION MENTIONED UNDER TROPICAL WAVES...MOSTLY
FAIR WEATHER CONDITIONS ARE BEING OBSERVED ELSEWHERE ACROSS
THE BASIN DUE TO A COMBINATION OF DRY AIR ALOFT AND SOME
SAHARAN DUST INTRUSION FROM THE PREVIOUS DAYS INTO THE
AREA. EASTERLY TRADE WIND FLOW OF 15-25 KT IS ACROSS MUCH OF THE
BASIN...EXCEPT HIGHER IN THE 25-30 KT WITH IN THE SW PORTION
FROM 12N-14N BETWEEN 70W-78W. THESE HIGHER WINDS ARE EXPECTED
TO LAST ANOTHER 24 HRS BEFORE DIMINISHING SOME.

ATLANTIC OCEAN...
EARLIER CONVECTIVE ACTIVITY NOTED ACROSS AND NEAR THE BAHAMAS
HAS DIMINISHED. THIS ACTIVITY WAS LEFT BEHIND BY THE TROPICAL
A BROAD AND STRONG 1031 MB HIGH PRESSURE SYSTEM CENTERED NNW OF
THE AZORES EXTENDS A SURFACE RIDGE AXIS TO THE WRN ATLC KEEPING
FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE REMAINDER OF THE
DISCUSSION AREA. THE FAIR WEATHER IS FURTHER ENHANCED BY A LARGE
AREA OF SAHARAN DUST EXTENDING FROM THE WEST AFRICA TO THE ERN
CARIBBEAN...AND LITTLE OVERALL CHANGE IS EXPECTED OVER THE NEXT
24-48 HRS.


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

$$

AGUIRRE





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