[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172331
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE 17 MAY 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA... GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

E ATLANTIC TROPICAL WAVE ALONG 20W S OF 13N MOVING W NEAR 10 KT.
THE VERTICAL SOUNDING FROM DAKAR INDICATES THAT THE WAVE IS
TILTED SLIGHTLY TO THE E WITH HEIGHT...WITH THE LOW-LEVEL
PASSAGE PRECEDING THE MID-LEVEL PASSAGE BY 12-24 HRS. SCATTERED
MODERATE CONVECTION FROM 3.5N-9N BETWEEN 18W-26W.

CENTRAL ATLANTIC TROPICAL WAVE ALONG 53W/54W S OF 12N MOVING W
15-20 KT. THE ITCZ IS INFLECTED TO THE N IN THE VICINITY OF THE
WAVE AXIS...N OF FRENCH GUIANA...SURINAME...AND GUYANA. THE
CAYENNE SOUNDING INDICATED A WEAK WAVE PASSAGE EARLY THIS
MORNING BEFORE 1200 UTC WHEN THE LOW-LEVEL WINDS TURNED SE AND
THE PWAT VALUES INCREASED TO 2.39". SCATTERED MODERATE
CONVECTION IS BEHIND THE WAVE FROM 3N-7N BETWEEN 48W-53W.
NUMEROUS MODERATE/STRONG INLAND FROM EQ-6N BETWEEN 52W-59W. IN
ADDITION...THE WAVE IS ALONG THE LEADING EDGE OF A SURGE OF
AFRICAN DUST THAT HAS BEEN TRAVERSING THE ATLC WATERS.

CENTRAL CARIBBEAN TROPICAL WAVE ALONG 71W/72W...NEAR LAKE
MARACAIBO...S OF 16N MOVING W NEAR 10 KT. THE WAVE CONTINUES TO
BE AFFECTED BY BROAD LOW PRES OVER THE W CARIBBEAN...SO IT
SIGNATURE IS DIFFICULT TO LOCATE. THE GREATEST CONCENTRATION OF
CONVECTION STRETCHES FROM THE MONA PASSAGE SW TO THE GUAJIRA
PENINSULA...WITH SCATTERED MODERATE FROM 10N-20N BETWEEN 67W-74W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N10W 7N20W 5N35W 3N47W 12N70W.
NUMEROUS MODERATE CONVECTION WITHIN 75 NM OF THE AXIS BETWEEN
20W-31W...PARTLY INFLUENCED BY TRPCL WAVE ALONG 20W. SCATTERED
MODERATE FROM 2N-5N BETWEEN 34W-42W. SCATTERED MODERATE 120 NM N
OF THE AXIS BETWEEN 47W-53W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD MID/UPPER LEVEL LONGWAVE TROF IS PUSHING SLOWLY EWD
ACROSS THE W GULF AND CNTRL MEXICO WITH A MID-LEVEL SHORTWAVE
CENTERED ABOUT 225 NM SW OF NEW ORLEANS LA. A LARGE AREA OF DRY
AIR IN THE MID/UPPER LEVELS HAS DIPPED DOWN THE W SIDE OF THE
TROF AND COVERS MUCH OF THE REGION W OF 90W. HOWEVER...THE
SHORTWAVE IS TRIGGERING SCATTERED SHOWERS/TSTMS S OF THE
LOUISIANA COAST FROM 26N-31N BETWEEN 88W-92W. THIS ACTIVITY LIES
AT THE N END OF A WEAKENING SFC TROF WHICH EXTENDS FROM 27N91W
SWD TO THE W YUCATAN COAST. ELSEWHERE...THE SUBTROPICAL JET RUNS
FROM THE ISTHMUS OF TEHUANTEPEC NE ACROSS S FLORIDA WITH MAX
WINDS NEAR 75 KT. THIS IS ADVECTING MID/HIGH LEVEL MOISTURE FROM
T.D. ONE-E IN THE PACIFIC TO THE NE...BUT KEEPING MOST OF THE
HIGH CLOUDS GENERALLY OVER THE CARIBBEAN BASIN.

CARIBBEAN...
AMPLIFIED UPPER LEVEL RIDGING HAS BECOME ESTABLISHED OVER THE
CARIBBEAN BASIN STRETCHING FROM AN ANTICYCLONE ALONG THE
COLOMBIA/VENEZUELA BORDER NWD ACROSS HISPANIOLA. A BROAD AREA OF
LOW PRES CONTINUES TO FESTER OVER THE W PART OF THE REGION WITH
ONE CIRCULATION NOTED BETWEEN JAMAICA AND SE CUBA...AND THE
OTHER CLOSE TO THE PANAMA CANAL NEAR 12N80W. NEITHER LOW IS VERY
WELL-DEFINED AND ARE CONNECTED BY AN ELONGATED SFC TROF. WIDELY
SCATTERED MODERATE CONVECTION IS NEAR THE SRN LOW S OF 14N
BETWEEN 77W-83W. OTHER CLUSTERS OF SCATTERED MODERATE ARE
FOCUSED OVER THE CNTRL CARIBBEAN DRIFTING NEAR HISPANIOLA AND
PUERTO RICO...AND WILL LIKELY BRING ANOTHER ROUND OF HEAVY
RAINFALL TO THE AREA OVERNIGHT AND ON WED. ELSEWHERE...WIDELY
SCATTERED MODERATE CONVECTION RUNS ALONG THE CNTRL AMERICAN
LANDMASS FROM PANAMA TO GUATEMALA...AND THIS REGION MAY ALSO
EXPERIENCE THE THREAT OF PROLONGED HEAVY RAINFALL LATER IN THE
WEEK. T.D. ONE-E IN THE PACIFIC OCEAN IS CURRENTLY CENTERED
ABOUT 400 NM SW OF GUATEMALA AND EL SALVADOR AND IS EXPECTED TO
APPROACH THE COAST LATE THU AS A STRONG TROPICAL STORM. THE
SYSTEM WILL CROSS CNTRL AMERICA...PRODUCING VERY HEAVY RAINFALL
WITH POSSIBLE FLOODING IN THE MOUNTAINOUS TERRAIN...AND COULD
AFFECT THE NW CARIBBEAN EARLY IN THE WEEKEND.

ATLANTIC...
UPPER LEVEL RIDGING IS AMPLIFYING OUT OF THE CARIBBEAN NWD OVER
THE W ATLC WATERS WITH THE SUBTROPICAL JET RIDING FROM S FLORIDA
NE TOWARDS BERMUDA. A SFC TROF EXTENDS FROM A SFC LOW BETWEEN
JAMAICA AND SE CUBA NE ACROSS THE SRN BAHAMAS THEN E TO 21N65W N
OF PUERTO RICO. SCATTERED MODERATE CONVECTION IS LOCATED
PRIMARILY S OF THE AXIS MOVING FROM THE DOMINICAN REPUBLIC EWD
TOWARDS PUERTO RICO. FARTHER E...A SECOND PIECE OF THIS TROF
STRETCHES OVER THE CNTRL ATLC ALONG 19N57W 24N50W 32N42W AND A
DIGGING UPPER TROF ALONG 50W IS ENHANCING SCATTERED MODERATE
CONVECTION FROM 17N-26N BETWEEN 42W-47W. WITH FAVORABLE UPPER
DIFFLUENCE...A SFC LOW IS EXPECTED TO DEVELOP ALONG THE TROF
WITHIN THE NEXT 24 HRS. TO THE E...SPLIT UPPER FLOW IS BETWEEN
30W-40W WITH RIDGING OVER THE SUBTROPICS AND TROUGHING OVER THE
TROPICS. THE TROF IS PENETRATING SWD TO THE EQUATOR AND IS
ENHANCING ITCZ CONVECTION E OF 30W. A MID/UPPER LOW IS CENTERED
JUST SW OF THE CANARY ISLANDS NEAR 27N20W DRIFTING TO THE S BUT
IS CAUSING NO SIGNIFICANT WEATHER. SAHARAN DUST CONTINUES TO
SPEW OFF THE W COAST OF AFRICA RUNNING S OF A LINE ALONG 25N15W
17N30W 16N40W.

$$
BERG


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