[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 04 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...
A 1013 MB LOW PRES SYSTEM IS CENTERED NEAR 11N44W OR ABOUT 1000
NM E OF THE LESSER ANTILLES. THE CIRCULATION IS WELL-DEFINED
WITH THE LOW-LEVEL CENTER CLEARLY SEEN ON SATELLITE IMAGES AS IT
IS EXPOSED TO THE N OF A WEAKENING BAND OF CONVECTION WITHIN 120
NM SSW OF THE CENTER. HOWEVER...THERE IS STILL POTENTIAL FOR
DEVELOPMENT OVER THE NEXT DAY OR SO BEFORE CONDITIONS BECOME
LESS FAVORABLE.

...TROPICAL WAVES...
A TROPICAL WAVE IS TITLED ALONG 56W/57W MOVING W NEAR 15 KT.
SHOWER ACTIVITY IS MINIMAL LIKELY CAPPED BY THE STRONGLY
SUBSIDENT ENVIRONMENT THAT IT IS ENTRENCHED IN. DESPITE THE LACK
OF DEEP MOISTURE...SATELLITE IMAGERY AND BUOY DATA SHOW ITS
PRESENCE WITH A SURGE-LIKE STRUCTURE...TURNING IN THE SFC WINDS
AND SLIGHTLY LOWER PRES NEAR THE AXIS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N14W 6N22W 5N30W 9N39W 10N50W
11N59W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 90 NM EITHER SIDE
OF THE AXIS E OF 29W AND BETWEEN 55W-59W.

...DISCUSSION...
GULF OF MEXICO...
ACTIVE WEATHER CONTINUES ACROSS THE NW GULF...SE TEXAS AND WRN
LOUISIANA...ROUGHLY N OF 28N W OF 91W. THESE NUMEROUS SHOWERS
AND TSTMS ARE BEING PRODUCED BY UPPER DIFFLUENCE AND A WEAK SFC
TROUGH OF LOW PRES OVER S TEXAS. IN THE E GULF...A 1015 MB LOW
IS CENTERED BETWEEN FT MYERS AND TAMPA FLORIDA WITH A
DISSIPATING FRONT EXTENDING NW TO LOUISIANA. THIS BOUNDARY IN
COMBINATION WITH DIFFLUENCE ALOFT...BETWEEN A LARGE ELONGATED
TROUGH NE OF THE REGION AND UPPER RIDGING OVER THE NW GULF...IS
FIRING SCATTERED SHOWERS AND TSTMS WITHIN 60 NM EITHER SIDE OF
THE FRONT. WEAK 1017 MB SFC HIGH PRES CENTER IS LOCATED IN THE
SE GULF. TIGHTENED GRADIENT BETWEEN THIS HIGH AND LOW PRES OVER
TEX/MEX IS PRODUCING MODERATE SELY WINDS ACROSS THE W GULF. THE
UPPER FLOW IS MOSTLY N-NELY CAUGHT BETWEEN AN UPPER RIDGE OVER
THE EPAC AND AN UPPER LOW OVER THE NW CARIB. THIS FLOW IS
ADVECTING BROKEN HIGH LEVEL CLOUDINESS ACROSS THE BULK OF THE
AREA.

CARIBBEAN SEA...
A SURGE OF DRY AIR ALOFT CONTINUES TO PROPAGATE W ACROSS THE
CARIB ADVECTED TO ABOUT 76W FROM THE TROPICAL ATLC. THIS STABLE
AIRMASS IS PROVIDING FAIR WEATHER ACROSS THIS AREA. THERE IS
SLIGHTLY MORE MOISTURE FURTHER W SUPPORTED BY AN UPPER LOW
SPINNING ABOVE THE NW CARIB NEAR 18N86W. BUT EVEN HERE...DEEP
MOISTURE IS CONFINED TO THE SW CARIB AND OVER PANAMA/COSTA
RICA...TIED TO THE ITCZ. A SMALLER LESS DEFINED UPPER LOW IS
LOCATED IN THE WINDWARD PASSAGE GENERATING A FEW SHOWERS AND
TSTMS. AT THE SFC...A 1124 Z QSCAT PASS SHOWED A LARGE AREA OF
20-30 KT ELY TRADES ACROSS MUCH OF THE CENTRAL AND W PORTIONS.
THESE STRONG WINDS ARE CARRYING TYPICAL LOW CLOUD STREAMERS WITH
EMBEDDED ISOLATED SHOWERS ACROSS THE REGION. LITTLE CHANGE IS
EXPECTED TOMORROW.

ATLANTIC OCEAN...
A STATIONARY FRONTAL SYSTEM ENTERS THE AREA NEAR 32N56W AND
EXTENDS WSW TO 27N72W THEN LIFTS NWD AS A WARM FRONT ALONG
29N79W TO A 1015 MB LOW OVER W CENTRAL FLORIDA. AN ILL-DEFINED
PREFRONTAL TROUGH LIES S OF THE FRONT ALONG 25N/26N BETWEEN
70W-77W. LOW-LEVEL CONVERGENCE NEAR THESE LOW-LEVEL BOUNDARIES
COMBINED WITH MOIST UPPER SWLY FLOW AND DIFFLUENCE...BETWEEN A
LARGE ELONGATED TROUGH N OF THE REGION AND UPPER RIDGING IN THE
GULF AND CENTRAL ATLC...IS PRODUCING SCATTERED SHOWERS AND TSTMS
WITHIN 90 NM EITHER SIDE OF THE FRONTS. FARTHER E...RIDGING
DOMINATES BOTH AT THE SFC AND ALOFT. THE SFC AZORES HIGH IS
ANALYZED 1032 MB NEAR 36N27W. THIS HIGH IS PRODUCING A LARGE
AREA OF MODERATE TRADES ACROSS THE ATLC. STRONG NLY WINDS ARE
NEAR THE AFRICAN COAST DUE TO THE TIGHTENING PRES GRADIENT
BETWEEN THE HIGH AND INVERTED TROUGHING OVER THE CONTINENT.
THREE UPPER HIGHS ARE PROVIDING A VERY STABLE AIRMASS ACROSS THE
CENTRAL AND E ATLC WITH ONLY LOW-LEVEL STABLE STRATOCUMULUS
CLOUDS SEEN ACROSS MUCH OF THE BASIN.

$$
CANGIALOSI




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