[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED 16 MAR 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N3W 1N25W 2N40W EQ53W. SCATTERED
STRONG CONVECTION IS MOVING OFF THE SW COAST OF AFRICA FROM
2N-10N BETWEEN 7W-13W. WIDELY SCATTERED MODERATE CONVECTION
WITHIN 90 NM EITHER SIDE OF AXIS FROM 20W-42W.

...DISCUSSION...

GULF OF MEXICO...
COMPLEX PATTERN UNFOLDING OVER THE GLFMEX AS YET ANOTHER S
STREAM SHORTWAVE TROUGH MOVES FROM THE E PACIFIC INTO MEXICO.  A
STRENGTHENING UPPER JET IN EXCESS OF 100 KT EXTENDS AROUND THE
E SIDE OF THE TROUGH FROM NE MEXICO NEWD OVER THE E UNITED
STATES. DYNAMICS/LIFT NEAR THE ENTRANCE REGION OF THE JET IS
PRODUCING AN AREA OF NUMEROUS SHOWERS/THUNDERSTORMS OVER THE NE
GULF AND FLORIDA PANHANDLE. AT THE SURFACE...QUASI-STATIONARY
FRONT EXTENDS FROM THE SE UNITED STATES ACROSS THE FLORIDA
PANHANDLE TO A 1004 MB FRONTAL LOW NEAR 27N90W.  A COLD FRONT
EXTENDS FROM THIS LOW SW TO THE COAST OF MEXICO NEAR TAMPICO
THEN AS A STATIONARY FRONT NW AGAINST THE E SLOPES OF THE SIERRA
MADRE ORIENTAL MOUNTAINS.  AREA OF LOW PRESSURE IS EXPECTED TO
MOVE NEWD AND STRENGTHEN SWEEPING THE COLD FRONT ACROSS THE
GLFMEX AND FLORIDA DURING THE NEXT 24-36 HR.  THE STRONGEST
SHOWERS/THUNDERSTORMS...CURRENTLY OVER THE NE GULF...ARE
EXPECTED TO LIFT QUICKLY NEWD ACROSS N FLORIDA THIS EVENING AND
TONIGHT EXITING THE AREA AFTER MIDNIGHT.  NUMERICAL GUIDANCE
INDICATES A SECOND ROUND OF STRONG SHOWERS/THUNDERSTORMS WILL
FORM OVER THE SE GULF TOMORROW THEN MOVE EWD OVER THE S HALF OF
FLORIDA.  THE FRONT IS THEN EXPECTED TO CLEAR S FLORIDA LATE THU
INTO THU NIGHT WITH POST-FRONTAL NLY FLOW ACROSS THE ENTIRE AREA
BY FRI

CARIBBEAN...
THE PATTERN REMAINS HIGH AND DRY OVER THE CARIBBEAN AS STRONG
MIDDLE TO UPPER LEVEL RIDGING CONTINUES TO DOMINATE THE ENTIRE
AREA. MEAN RIDGE AXIS EXTENDS FROM THE NE COAST OF VENEZUELA NW
OVER CENTRAL AMERICA NEAR NICARAGUA. MODERATE/STRONG SUBSIDENCE
IS PRODUCING VERY DRY/STABLE CONDITIONS ALOFT.  LOW LEVEL
MOISTURE IS ALSO LIMITED WITH MINIMAL SHOWER ACTIVITY ACROSS THE
AREA.  CONDITIONS ARE EXPECTED TO REMAIN DRY OVER THE E
TWO-THIRDS OF THE AREA THROUGH MID-WEEK.  AN APPROACHING COLD
FRONT FROM THE GLFMEX SHOULD PROVIDE INCREASING CLOUDINESS AND
WIDELY SCATTERED SHOWERS AS IT MOVES INTO THE AREA LATE THU INTO
FRI MORNING.

ATLANTIC...
LARGE AMPLITUDE RIDGE-TROUGH-RIDGE PATTERN PREVAILS OVER THE
BULK OF THE SUBTROPICAL ATLANTIC WITH A BROAD MID/UPPER LEVEL
RIDGE W OF 60W...DEEP LAYERED TROUGH OVER THE CENTRAL ATLC
BETWEEN 35W-60W...AND RIDGE OVER THE E ATLC E OF 35W INTO NW
AFRICA. THE BULK OF THE ACTIVE WEATHER IS FOCUSED ALONG AND
AHEAD OF A COLD FRONT OVER THE CENTRAL ATLC WHICH ENTERS THE
AREA NEAR 32N40W AND EXTENDS SW ALONG 23N55W TO 23N70W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF
THE FRONT N OF 27N. SIMILAR ACTIVITY IS WITHIN 240 NM E OF A
PRE-FRONTAL TROUGH FROM 31N33W TO 20N50W.  SHOWER/THUNDERSTORM
ACTIVITY SHOULD CONTINUE ALONG AND E OF FRONT THROUGH FRIDAY
WHEN THE UPPER TROUGH BEGINS TO LIFT NEWD. W OF THE FRONT...HIGH
PRESSURE AND POST-FRONTAL NLY FLOW PREVAILS WITH THE TYPICAL
COLD AIR STRATOCUMULUS CLOUDS PREVAILING TO 70W.  THE E ATLC
REMAINS RELATIVELY DRY/TRANQUIL WITH LATEST VISIBLE SATELLITE
IMAGERY SHOWING NEARLY CLOUD FREE CONDITIONS S OF 25N E OF 35W
IMPLYING VERY DRY AIR HAS OVERSPREAD THE AREA.  LOOKING
UPSTREAM...COMPLEX SURFACE LOW OVER THE GLFMEX IS EXPECTED TO
LIFT NEWD OVER N FLORIDA AN STRENGTHEN TONIGHT SWEEPING A COLD
FRONT INTO THE W ATLC BY EARLY FRI.  INCREASING CLOUDINESS IS
ALREADY NOTED OVER THE EXTREME W ATLC WATERS AND
SHOWERS/THUNDERSTORMS SHOULD BEGIN DEVELOPING LATER THIS
EVENING.

$$
RHOME



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