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Tropical Discussion
 
(Latest Discussion - Issued 1926Z Feb 18, 2020)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
226 PM EST TUE FEB 18 2020

TROPICAL DISCUSSION FOR FEBRUARY 18/18 UTC: THE SUBTROPICAL RIDGE
IS THE DOMINANT FEATURE OVER THE BASIN...WITH MID/UPPER LEVEL AXIS
SPANNING BETWEEN THE SOUTHERN/CENTRAL STATES OF MEXICO AND THE
EASTERN CARIBBEAN ISLES. AT 500 HPA THIS IS TO CENTER ON A CLOSED
HIGH THAT MEANDERS OVER WESTERN CUBA DURING THE NEXT COUPLE OF
DAYS...WITH HIGH TO MEANDER WEST TO THE YUCATAN LATER ON THURSDAY.
MEANWHILE...AS THE RIDGE HOLDS...IT IS TO SUSTAIN A FAIRLY STRONG
TRADE WINDS INVERSION OVER MEXICO...CENTRAL AMERICA...GREATER
ANTILLES...ISLAND CHAIN TO NORTHERN SOUTH AMERICA.

AS THE MID LEVEL RIDGE HOLDS...A POLAR TROUGH IS TO STREAM TO THE
NORTH. THIS IS TO LIFT ACROSS THE USA AS THE WEEK WEARS ON...WITH
THE TROUGH EXITING THE EASTERN SEABOARD ON FRIDAY. AT LOW
LEVELS...THE TROUGH ALOFT SUSTAINS A MEANDERING FRONT OVER THE
SOUTHERN USA. THIS IS TO REMAIN NEARLY STATIONARY THROUGH
THURSDAY. EARLY ON FRIDAY...BUILDING RIDGE TO THE NORTH WILL DRIVE
THIS BOUNDARY SOUTH ACROSS THE WESTERN GULF WHILE FAVORING A
STRONG NORTHERLY FLOW. THROUGH FRIDAY AFTERNOON THE FRONT IS TO
THEN MIGRATE ACROSS THE GULF/FLORIDA...REACHING THE NORTHWEST
BAHAMAS-WESTERN CUBA WHILE TRAILING ACROSS THE NORTHERN YUCATAN TO
VERACRUZ LATER IN THE DAY. OVER NORTHERN CHIHUAHUA IS TO FAVOR
LIGHT SNOWFALL ON THURSDAY...WITH ACCUMULATION OF 00-05CM/DAY AND
MAXIMA OF 10CM. OVER VERACRUZ MEXICO THE STRONG NORTHERLIES ARE TO
RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM ON
THURSDAY...WHILE ON FRIDAY EXPECTING ACCUMULATION OF 05-10MM/DAY
AND MAXIMA OF 15-20MM OVER SOUTHERN MEXICO TO NORTHERN HONDURAS AS
ENHANCED BY THE BRISK NORTHERLIES ACROSS THE GULF TO THE WESTERN
CARIBBEAN. OVER THE NORTHWEST BAHAMAS-WESTERN CUBA EXPECTING
ACCUMULATION OF 00-05MM/DAY AND MAXIMA OF 10MM LATER IN THE WEEK.

FARTHER EAST...A MID LEVEL SHORT WAVE TROUGH STREAMING ACROSS THE
WESTERN ATLANTIC IS TO REMAIN NORTH OF THE GREATER ANTILLES EARLY
IN THE CYCLE. BUT AS IT CLEARS THE EASTERN FRINGES OF THE
MID/UPPER LEVEL RIDGE THE TROUGH IS TO AMPLIFY ON WEDNESDAY. THE
AMPLIFYING TROUGH IS TO THEN PHASE WITH A MEANDERING TUTT LOW EAST
OF THE ISLANDS. THIS WILL SUSTAIN THE GRADUAL INTENSIFICATION OF
THE MID LEVEL CIRCULATION ON WEDNESDAY-THURSDAY. AS THE TROUGH
DEEPENS...THIS IS TO THEN INCITE THE GENERATION OF SHORT WAVE
PERTURBATIONS AND SHALLOW CONVECTION IN THE EASTERLY TRADES. AS
THE TROUGH ENHANCES CONVECTIVE INSTABILITY...MOST ACTIVE IS
EXPECTED DURING THE NIGHTTIME HOURS. ACROSS THE FRENCH-LEEWARD
ISLANDS TO PUERTO RICO THIS WILL SUSTAIN ACCUMULATION OF
00-05MM/DAY AND MAXIMA OF 10MM. HIGHER AMOUNTS ARE EXPECTED OVER
TRINIDAD AND TOBAGO EARLY IN THE CYCLE...WITH ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15MM. OVER THE NORTHERN GUIANAS ONLY
EXPECTING ACCUMULATION OF 00-05MM/DAY WITH WIDELY ISOLATED MAXIMA
OF 10MM.

AS THE MID LEVEL RIDGE WEAKENS ACROSS THE BASIN...THE GLOBAL
MODELS CONSISTENTLY AGREE ON A GRADUAL INCREASE IN DIURNAL
CONVECTION ALONG AND WEST OF THE ANDES OVER COLOMBIA. OVER EJE
CAFETERO TO THE NORTHWEST INITIALLY EXPECTING ACCUMULATION OF
00-05MM/DAY AND MAXIMA OF 10MM. THROUGH THURSDAY THIS INCREASES TO
15-20MM/DAY AND MAXIMA OF 35-70MM...WHILE ON FRIDAY THE MAXIMA
PEAKS AT 20-30MM/DAY. ON THE CAUCA VALLEY TO THE SOUTHWEST
INITIALLY EXPECTING RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM. ON WEDNESDAY THE MAXIMA INCREASES TO 25-50MM...WHILE ON
THURSDAY-FRIDAY IT IS TO PEAK AT 35-70MM.

TROPICAL/EASTERLY WAVES/TRADE WIND SURGES FROM 00 UTC:
INITIAL 24    36    48    60    72    84    96    TYPE   SOF
NONE

CLARKE...CINWS (CAYMAN ISLANDS)
TYNES...BMS (THE BAHAMAS)
DAVISON...WPC (USA)