194
FXCA20 KWBC 161834
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
233 PM EDT WED MAY 16 2012
DISCUSSION FROM MAY 15/00 UTC: AN UPPER LEVEL RIDGE IS INITIALIZED
WITH AXIS EXTENDING FROM THE EASTERN PACIFIC/SOUTHERN MEXICO...
ACROSS CENTRAL AMERICA TO THE CENTRAL CARIBBEAN/NORTHWEST SOUTH
AMERICA. A POLAR TROUGH OVER THE EASTERN USA/NORTHERN GULF OF
MEXICO IS PRESSING AGAINST THIS AXIS. THROUGH 36-48 HRS THE TROUGH
IS TO PULL TO THE EAST-NORTHEAST ACROSS THE EASTERN
USA...MEANWHILE FAVORING THE GRADUAL EROSION AND WEAKENING OF THE
RIDGE AXIS OVER SOUTHERN MEXICO/NORTHERN CENTRAL AMERICA. ANOTHER
PERTURBATION IS TO CLOSELY FOLLOW...WITH TROUGH ACROSS SOUTHWEST
USA TO NORTHERN STATES OF MEXICO BY 48 HRS...INTO THE NORTHERN
GULF BY 72 HRS. THIS WILL ADD TO GRADUAL EROSION OF THE RIDGE OVER
THE SOUTHERN STATES OF MEXICO/YUCATAN PENINSULA. AT LOW LEVELS...A
POLAR TROUGH EXTENDS ACROSS THE EASTERN USA TO THE EASTERN GULF OF
MEXICO...WHILE A POLAR RIDGE TO THE WEST LIES OVER THE CENTRAL
PLAINS TO TEXAS. THE TROUGH SUSTAINS A WEAK BAROCLINIC BOUNDARY
INTO THE GULF OF MEXICO...BUT THIS IS FORECAST TO WEAKEN THROUGH
24 HRS. UNDER INFLUENCE OF THE RIDGE TO THE WEST...AND MEANDERING
TROUGH OVER THE EASTERN USA/GULF...A LONG FETCH NORTHERLY FLOW IS
TO PERSIST ACROSS THE WESTERN/CENTRAL GULF OF MEXICO TO THE
SOUTHERN STATES OF MEXICO. THIS WILL ENHANCE MOISTURE CONVERGENCE
ACROSS PORTIONS OF CAMPECHE-YUCATAN-TABASCO AND CHIAPAS IN
SOUTHERN MEXICO. IN THIS AREA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-30MM/DAY THROUGH 30 HRS...AND
00-05MM/DAY AND MAXIMA OF 10MM/DAY THEREAFTER. OTHER ACTIVITY IS
TO AFFECT MEXICO DF-PUEBLA-COLIMA/MICHOACAN... WHERE DIURNAL
CONVECTION WILL RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15MM/DAY. THROUGH DAY 03 THE MAXIMA WILL INCREASE TO
15-30MM/DAY.
ALTHOUGH UPPER LEVEL RIDGE TENDS TO ERODE OVER SOUTHERN MEXICO...
OVER THE CARIBBEAN/CENTRAL AMERICA IT WILL BE MORE RESILIENT.
DURING THE NEXT COUPLE OF DAYS IT WILL CENTER ON A HIGH OVER GULF
OF FONSECA...WITH AXIS TO MEANDER EAST ACROSS HONDURAS TO THE
CENTRAL CARIBBEAN BY 72-96 HRS. THE PERSISTENT RIDGE PATTERN WILL
STEER SHORT WAVE PERTURBATIONS ACROSS CUBA AND THE BAHAMAS. THESE
ARE TO INTERACT WITH SEA BREEZE CONVERGENCE TO ENHANCE CONVECTIVE
DEVELOPMENT OVER THESE ISLANDS. OVER THE CENTRAL/NORTHWEST BAHAMAS
EXPECTING ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM
THROUGH 36-48 HRS...AND AGAIN BY 72-84 HRS.
FURTHERMORE...AS AN UPPER LEVEL RIDGE PERSISTS OVER CENTRAL
AMERICA...IT WILL VENT DEEP CONVECTION IN ASSOCIATION WITH AN
INDUCED/INVERTED TROUGH OVER THE WESTERN CARIBBEAN. THE TROUGH
EXTENDS NORTH FROM GULF OF HONDURAS TO THE YUCATAN CHANNEL/EASTERN
GULF OF MEXICO. THIS TROUGH IS TO PERSIST DURING THE NEXT 84-96
HRS...WITH SOME OF THE MODELS SHOWING POSSIBLE STRENGTHENING OF
THIS AXIS LATER IN THE CYCLE. HOWEVER...IN A HIGH SHEAR
ENVIRONMENT...IT IS MORE LIKELY TO PERSIST AS AN OPEN TROUGH.
ALONG THE BASE OF THE TROUGH EXPECTING CONVECTIVE ENHANCEMENT
ACROSS WESTERN CUBA-BELIZE/QUINTANA ROO IN THE YUCATAN...WHERE IT
IS TO FAVOR RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF
50-100MM/DAY. THROUGH 72-96 HRS THIS IS FORECAST TO DECREASE TO
10-15MM/DAY AND MAXIMA OF 20-40MM/DAY. AS A TROUGH PERSISTS OVER
NORTHERN CENTRAL AMERICA...THE BEST MOISTURE CONVERGENCE IS
EXPECTED ACROSS THE SOUTHERN STATES OF MEXICO TO GUATEMALA-EL
SALVADOR/HONDURAS AND PORTIONS OF NICARAGUA. OVER SOUTHERN MEXICO
TO GUATEMALA EXPECTING RAINFALL AMOUNTS OF 25-50MM/DAY AND MAXIMA
OF 75-125MM/DAY THROUGH 36 HRS. THIS DECREASES TO 15-20MM/DAY AND
MAXIMA OF 25-50MM THROUGH 84-96 HRS...WHILE OVER EL
SALVADOR-HONDURAS AND NICARAGUA EXPECTING ACCUMULATION OF
25-50MM/DAY AND MAXIMA OF 75-125MM/DAY...FORECAST TO DECREASE
THROUGH 84-96 HRS. BY 72-96 HRS MOST ACTIVE IS EXPECTED ALONG THE
NORTH COAST WITH MAXIMA OF 40-80MM/DAY.
MID LEVEL HIGH IS INITIALIZED OVER THE WINDWARD PASSAGE OF
CUBA...ANCHORING A RIDGE OVER THE CENTRAL CARIBBEAN. UNDER
PRESSURE FROM AFOREMENTIONED MID/UPPER LEVEL PERTURBATIONS...THIS
RIDGE IS ALSO FORECAST TO WEAKEN THROUGH 48 HRS...TO BECOME NARROW
AND ELONGATED LATER IN THE CYCLE. THIS SUSTAINS A MID LEVEL CAP
ACROSS HISPANIOLA-PUERTO RICO/NORTHERN LEEWARD ISLANDS. THIS WILL
BE STRONG ENOUGH TO DELAY ONSET OF DIURNAL CONVECTION...BUT NOT
STRONG TO SUPPRESS IT. THE CAP WILL GRADUALLY WEAKEN THROUGH 42-48
HRS... ALLOWING FOR DEEPER MOISTURE TO POOL ACROSS THESE ISLANDS.
THE GFS IS RESPONDING TO CHANGE IN ENVIRONMENTAL CONDITIONS BY
SHOWING PWAT INCREASING FROM 35-40MM TO NEARLY 50MM BY 42-48
HRS...WITH K INDEX ALSO INCREASING TO THE LOW 30S IN RESPONSE TO
THE DEEPER LAYER INSTABILITY IN THE AREA. INITIALLY...DIURNAL
CONVECTION OVER THESE ISLANDS WILL RESULT IN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM/DAY. THROUGH 48-72 HRS THIS WILL
INCREASE TO 10-15MM/DAY AND MAXIMA OF 20-30MM/DAY.
DOWNSTREAM FROM THE CARIBBEAN RIDGE...AN UPPER LEVEL TROUGH
EXTENDS SOUTH ACROSS THE ISLAND CHAIN TO NORTHEAST VENEZUELA. THE
TROUGH IS TO MEANDER OVER THE EASTERN CARIBBEAN ISLANDS THROUGH
36-42 HRS... THEN MOVE EAST OF THE ISLAND CHAIN BY 60-72
HRS...WHILE TRAILING SOUTH TO GUYANA/EASTERN VENEZUELA. SHORT WAVE
PERTURBATIONS ROUNDING THE BASE OF THE TROUGH WILL ENHANCE
CONVECTION ACROSS THE SOUTHERN WINDWARD ISLANDS/NORTHEAST
VENEZUELA. AT LOW LEVELS...THE ATLANTIC ITCZ MEANDERS ALONG THE
NORTHERN GUIANAS INTO VENEZUELA. THE TROUGH ALOFT IS TO INTERACT
WITH THE CONVERGENCE ZONE TO ENHANCE ACTIVITY ACROSS THE GUIANAS
TO NORTHEAST VENEZUELA...WHERE WE EXPECT RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM/DAY.
PERTURBATIONS IN THE EASTERLIES...INITIALIZED AT 12UTC
INITIAL 24 36 48 60 72 84 TYPE
61W/62W 64W 67W 70W 73W 75W 78W TW
71W 74W 76W 78W 80W 82W 84W EW
TROPICAL WAVE ALONG 61W/62W AND SOUTH OF 12N IS INTERACTING WITH
THE ITCZ NORTH OF GUYANA AND MID/UPPER TROUGH OVER THE EASTERN
CARIBBEAN...FAVORING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-35MM/DAY AS IT ENTERS NORTHEAST VENEZUELA/SOUTHERN WINDWARD
ISLANDS. OVER CENTRAL-WESTERN VENEZUELA IT IS TO THEN FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY. MOST
INTENSE TO AFFECT LAKE MARACAIBO REGION IN NORTHWEST
VENEZUELA-SANTANDERES IN COLOMBIA/SIERRA NEVADA DE SANTA MARTA
WITH RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM/DAY.
OVER EJE CAFETERO IN COLOMBIA TO THE DARIEN IN PANAMA IT WILL
RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM.
AN EASTERLY WAVE ALONG 71W AND SOUTH OF 16N IS TO TRIGGER
SCATTERED CONVECTION ACROSS NORTHERN COLOMBIA WITH RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY...SIMILARLY
ACROSS EJE CAFETERO TO THE DARIEN IN PANAMA. OVER WESTERN
PANAMA/COSTA RICA EXPECT ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF
35-70MM/DAY.
ALSO AT 850 HPA...A BUILDING CELL OF THE SUBTROPICAL RIDGE IS TO
THEN TIGHTEN THE PRESSURE GRADIENT ACROSS THE CENTRAL/WESTERN
ATLANTIC TO THE EASTERN CARIBBEAN ISLANDS. IN THIS PATTERN WINDS
WILL GRADUALLY VEER TO THE SOUTHEAST WHILE INTENSITY INCREASES
FROM 10-15KT TO 20-25KT.
MARINERO...DGOA/MARN (EL SALVADOR)
SOLORZANO...SMN (HONDURAS)
GALVEZ...HPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page