[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 100522
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUN 10 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0500 UTC.

...SPECIAL FEATURE...
1005 MB LOW IS IN THE NW CARIBBEAN NEAR 19N85W DRIFTING
NORTHWARD.  THERE IS NO WELL-DEFINED CIRCULATION CENTER AS OF
YET BUT THE SYSTEM STILL SHOWS SIGNS OF BANDING FEATURES AND
LARGE (3-4 MB) 24 HOUR PRESSURE FALLS.  THE SYSTEM IS CLOSE TO
BECOMING A TROPICAL DEPRESSION AND ALL SIGNS GENERALLY POINT TO
IT DEVELOPING LATER TODAY.  COMPUTER MODEL GUIDANCE ROUGHLY
TAKE THE SYSTEM IN A NORTHWESTERLY DIRECTION TOWARD THE YUCATAN
CHANNEL AND INTO THE SOUTHERN GULF OF MEXICO BY ABOUT THIS TIME
TOMORROW.  AN UPPER TROUGH TO THE W OF THE CYCLONE HAS BEEN
GRADUALLY MOVING WESTWARD WITH AN EXPANSION OF AN UPPER
ANTICYCLONE CENTERED NEAR 18N83W.  FOR NOW.. THE PRIMARY THREAT
IS CONTINUED HEAVY RAINS OVER THE CAYMAN ISLANDS AND CENTRAL
CUBA WESTWARD AS SOME OF THOSE AREAS HAVE RECEIVED OVER 8 INCHES
OF RAIN.  SCATTERED MODERATE CONVECTION IS FROM 17N-21N BETWEEN
JAMAICA AND 85W.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 32W S OF 11N MOVING W 15 KT.  THE WAVE
HAS A PRETTY GOOD V-SIGNATURE ON NIGHTTIME VISIBLE SATELLITE
ALONG WITH SOME SCATTERED MODERATE TSTMS IN THE ITCZ WITHIN 90
NM OF 7N34W.

TROPICAL WAVE IS ALONG 57W/58W S OF 9N MOVING W 10-15 KT.  ANY
SIGNIFICANT WEATHER WITH THE WAVE IS INLAND OVER NORTHERN S
AMERICA.  COMPUTER MODELS SUGGEST THAT MOISTURE WITH THE WAVE
SHOULD STAY S OF THE WINDWARD ISLANDS.

TROPICAL WAVE IS ALONG 70W/71W S OF 10N MOVING W 10 KT. WAVE IS
FAIRLY LOW-LATITUDE WITH NO SIGNIFICANT WEATHER OVER WATER.  A
FEW TSTMS ARE INLAND OVER COLOMBIA/NW VENEZUELA ASSOCIATED WITH
THE WAVE.

TROPICAL WAVE IS ALONG 81W S OF 13N MOVING W 10 KT. THE SOUTHERN
EXTENSION OF THE WAVE IS PRODUCING SHOWERS/TSTMS OVER COSTA RICA
AND PANAMA.

ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 6N25W 5N45W 7N58W. WIDELY
SCATTERED MODERATE CONVECTION WITHIN 45 NM OF LINE 8N37W 5.5N45W
7N53W AND S OF 4.5N W OF 48W.  ISOLATED MODERATE CONVECTION S OF
5N BETWEEN 33W-37W.  SCATTERED MODERATE CONVECTION IS FROM 4N-7N
BETWEEN 21W-27W. AND WITHIN 60 NM OF 9.5N18W.

...DISCUSSION...
GULF OF MEXICO...
UPPER RIDGING COVERS THE NORTHERN GULF WITH A CENTER JUST S OF
SE LOUISIANA.  MODERATE/STRONG SUBSIDENCE IS CONTROLLING THE
REGION N AND W OF AN UPPER TROUGH EXTENDING FROM SW FLORIDA TO
THE YUCATAN PENINSULA.  THIS UPPER TROUGH IS MOVING SLOWLY
WESTWARD AS UPPER RIDGING POKES INTO THE SE GULF OF MEXICO.  AS
THE TROUGH SLIDES WESTWARD.. IT SHOULD ALLOW DEEP TROPICAL
MOISTURE IN ASSOCIATION WITH THE TROPICAL DISTURBANCE IN THE NW
CARIBBEAN TO SPREAD NORTHWARD... INCREASING THE THREAT OF RAIN
FOR S FLORIDA TOMORROW AND MUCH HIGHER FOR SUN.  THE NORTHERN
GULF COAST WEST OF LOUISIANA LOOKS QUITE DRY FOR THIS TIME OF
THE YEAR THOUGH RAIN CHANCES MIGHT BE ON THE INCREASE IN THE
EASTERN GULF BY EARLY NEXT WEEK.

CARIBBEAN SEA...
THE MAIN WEATHER INTEREST IN THIS AREA IS A 1005 MB LOW IN THE
NW CARIBBEAN THAT IS PRODUCING WIDESPREAD CLOUDINESS AND SHOWERS
OVER THE REGION AND ADJACENT LAND AREAS. SEE SPECIAL FEATURE FOR
DETAILS.  UPPER RIDGE AXIS EXTENDS FROM NEAR JAMAICA EASTWARD TO
JUST N OF PUERTO RICO WITH ELY WINDS ALOFT OVER THE CARIBBEAN
SAVE FOR A SMALL AREA OF UPPER TROUGHING IN THE FAR SE WINDWARD
ISLANDS.  UPPER CONVERGENCE IS LEADING TO A DRY WEATHER PATTERN
OVER THE EASTERN CARIBBEAN WITH ONLY A FEW TSTMS IN THE SW
CARIBBEAN AND ALONG THE NW COAST OF COLOMBIA.  THE GFS INCREASES
THE DEEP-LAYERED MOISTURE SOME IN THE NE CARIBBEAN BY LATE SUN
WHICH COULD PROVOKE A FEW MORE SHOWERS/TSTMS IN THAT AREA.  NEXT
SIGNIFICANT WAVE IS FORECAST TO ENTER THE E CARIBBEAN EARLY TUE
AND MIGHT BE THE MOST CONVECTIVELY-ACTIVE OF THE SEASON SO FAR.

ATLANTIC OCEAN...
UPPER TROUGH NOSES INTO THE NW PART OF THE AREA ALONG 70W N OF
27N INCREASING THE NUMBER OF MID/UPPER CLOUDS N OF 27N ALONG
WITH A FEW SHOWERS.  LARGE MID-OCEANIC TROUGH IS SITTING FROM
31N41W 14N50W THEN INTO THE WINDWARD ISLANDS NEAR ST LUCIA WITH
A MID/UPPER LOW NEAR 26N45W ALONG THE TROUGH.  MODERATE/STRONG
SUBSIDENCE CONTROLS MUCH OF THE REGION WITHIN ABOUT 300 NM OF
THE TROUGH EXCEPT FOR ISOLATED SHOWERS/TSTMS WITHIN 120 NM OF
THE LOW CENTER... WHICH HAS A WEAK SURFACE TROUGH REFLECTION.
IN THE E ATLC.. HIGH PRESSURE HAS BUILT UP IN THE MID/UPPER
LEVELS WITH A CENTER NEAR 20N22W.. MUCH FARTHER N THAN AVERAGE
FOR EARLY JUNE.  RIDGE AXIS EXTENDS TO 19N30W 8N40W 8N80W..
FARTHER S THAN AVERAGE IN THE CENTRAL ATLC.  THIS UPPER PATTERN
IS FAVORABLE TO SUPPORT A FAIR NUMBER OF TSTMS IN THE ITCZ AND
SOMEWHAT CONVECTIVE WAVES.  TYPICAL STRATOCUMULUS DECK COVERS
THE CENTRAL/E ATLC WITH THE SUBTROPICAL RIDGE IN CONTROL..
ALBEIT A TAD WEAKER THAN AVERAGE.  COMPUTER MODELS SUGGEST THAT
THE NEXT FEW WAVES WILL BE FAIRLY STRONG WITH A MUCH FARTHER
NORTHWARD EXTENT THAN THE RECENT BATCH W OF 50W.  THIS IS
POSSIBLY DUE TO A LARGE-SCALE DIVERGENCE PATTERN ... SOMEWHAT
RELATED TO THE MADDEN-JULIAN OSCILLATION ... SHIFTING EASTWARD
FROM THE EASTERN PACIFIC INTO THE ATLC DURING THE NEXT WEEK OR
SO.

$$
BLAKE

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