102
FXCA20 KWBC 272017
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
316 PM EST FRI DEC 27 2024
FORECAST BULLETIN 27 DEC 2024 AT 20 UTC
THE DIVERGENT PHASE OF THE MADDEN-JULIAN OSCILLATION (MJO) WILL
PREVAIL THROUGH THE 3-DAY FORECAST CYCLE... CONTINUING INTO THE
START OF THE NEW YEAR. THIS WILL FAVOR WIDESPREAD CONVECTIVE MODES
IN THE NEXT WEEK.
TWO UPPER LEVEL TROUGHS WILL BEGIN TO AFFECT THE TROPICAL REGION
STARTING TODAY THROUGH MONDAY. THE FIRST UPPER LEVEL TROUGH IS
RAPIDLY MOVING FROM THE WESTERN UNITED STATES... REACHING THE
MEXICAN-TEXAS BORDER BY EARLY SATURDAY MORNING... WHEN IT IS ALSO
EXPECTED TO BEGIN AMPLIFYING. BY MONDAY MORNING... THE TROUGH AXIS
WILL BE LOCATED OVER THE EASTERN UNITED STATES. THE SECOND UPPER
LEVEL TROUGH IS CURRENTLY LOCATED NEAR 35N59W AND WILL BEGIN TO
AMPLIFY TODAY. BY THE END OF WEEKEND...THE TROUGH WILL BE LOCATED
OVER THE CENTRAL ATLANTIC. THIS WEEKEND... THE TWO UPPER LEVEL
TROUGHS WILL HELP WEAKEN AN UPPER LEVEL RIDGE CURRENTLY LOCATED
ACROSS THE WESTERN ATLANTIC.
ENHANCED SOUTHERLY WIND WILL CONTINUE TO DOMINATE EAST GULF OF
MEXICO AND THE NORTHWEST CARIBBEAN THROUGH SUNDAY EVENING...
PRIMARILY IMPACTING PRECIPITATION PATTERNS IN WESTERN CUBA. THIS
WIND SHIFT FROM EASTERLIES TO MORE SOUTHERLIES WILL BE DRIVEN BY
THE CONFLUENCE BETWEEN THE PERIPHERIES A HIGH PRESSURE SYSTEM OFF
THE ATLANTIC COAST OF THE USA AND A LOW PRESSURE SYSTEM DEVELOPING
IN THE CENTRAL USA ON SATURDAY. A DEVELOPING COLD FRONT IN CENTRAL
TEXAS ON SATURDAY IS ALSO EXPECTED TO FURTHER CONTRIBUTE TO THE
ENHANCEMENT OF SOUTHERLY FLOW IN THIS REGION. AS THIS COLD FRONT
PROGRESSES EASTWARD INTO SOUTHEAST SOUTH CAROLINA AND GEORGIA BY
SUNDAY... AN INCREASE IN MOISTURE CONVERGENCE IS EXPECTED IN
WESTERN CUBA THROUGH SUNDAY EVENING. TODAY AND SATURDAY... THERE
IS A MARGINAL RISK FOR SEVERE WEATHER DUE TO THE PRESENCE OF
UPPER LEVEL DIVERGENCE AND MID-LEVEL SHORTWAVE TROUGHS.
IN MEXICO AND NORTHERN CENTRAL AMERICA... THERE IS SOME
UNCERTAINTY REGARDING THE HIGH PRECIPITATION TOTALS THE MODEL
GUIDANCE IS SUGGESTING FOR QUINTANA ROO AND YUCATAN. THE FORECAST
MODELS ARE IN DISAGREEMENT REGARDING THE MOISTURE CONTENT IN THE
NORTHWEST CARIBBEAN FOR THE NEXT THREE DAYS. THE GFS IS INDICATING
A LESS INTENSE MOISTURE PLUME MOVING INTO THE YUCATAN PENINSULA...
HONDURAS... AND BELIZE COMPARED TO THE ECWMF. HOWEVER... ECWMF IS
INITIALIZING MOISTURE CONTENT IN THE REGION WITH GREATER ACCURACY
THAN THE GFS. DUE TO ENHANCED SOUTHERLY FLOW FROM THE NORTHWEST
CARIBBEAN SEA INTO THE SOUTHEAST USA AHEAD OF THE AFOREMENTIONED
COLD FRONT... WE EXPECT THE AVAILABLE MOISTURE TO REMAIN ABOVE
NORMAL ACROSS THE WESTERN CARIBBEAN INTOTHE YUCATAN PENINSULA
TODAY THROUGH SUNDAY MORNING. THUS... WE ARE LEANING MORE TOWARDS
THE ECWMF FOR THIS REGION. BY SUNDAY INTO MONDAY... WE EXPECT THE
LOW LEVEL FLOW TO RETURN TO A MORE EASTERLY DIRECTION ACROSS THIS
REGION.
IN PANAMA AND COSTA RICA... A LOW PRESSURE SYSTEM IS EXPECTED TO
DEVELOP OFF THE PACIFIC COAST OF COSTA RICA TONIGHT INTO SATURDAY
MORNING. THE CYCLONIC FLOW WILL DIRECTLY IMPACT PRECIPITATION
PATTERNS THROUGH THE NEXT THREE DAYS. HOWEVER... UNCERTAINTY
EXISTS IN THE LOCATION OF THIS LOW PRESSURE SYSTEM FOR SUNDAY INTO
MONDAY. THE GFS KEEPS THE LOW PRESSURE SYSTEM STALLED IN THE
REGION... WHEREAS THE ECWMF HAS IT MOVING OUT TO SEA INTO THE
PACIFIC. AS A RESULT... THE GFS IS INDICATING SIGNIFICANTLY HIGHER
ACCUMULATIONS IN THIS REGIONS COMPARED TO OTHER MODELS. BECAUSE
THE LOW LEVEL FLOW IS STILL FAVORABLE FOR MOISTURE CONVERGENCE AND
THERE WILL BE SOME UPPER LEVEL DIVERGENCE IS ASSOCIATION WITH
PRE-EXISTING CONVECTION... WE ANTICIPATE THE RAINFALL TOTALS TO
HAVE A MAXIMA NEAR MAXIMA OF 20-35MM IN PANAMA AND COSTA RICA.
IN TROPICAL SOUTH AMERICA... THE BOLIVIAN HIGH CONTINUES TO
DOMINATE THE REGION... AND THUS WE EXPECT CONVECTION ALONG ITS
PERIPHERY DUE TO VENTILATION. IN NORTHWESTERN BRAZIL... DIFFLUENCE
IN THE UPPER LEVELS AND THE SACZ FARTHER SOUTH WILL CONTINUE TO
ASSIST IN THE DEVELOPMENT FOR CONVECTION IN THE REGION. IN
COLOMBIA... WESTERLY FLOW FROM THE PACIFIC WILL CONTINUE TO
CONVERGE ALONG THE COAST THROUGH THE NEXT 3 DAYS. AS A RESULT...
MOISTURE CONVERGENCE IS EXPECTED AND HIGH PRECIPITATION TOTALS.
ELSEWHERE IN NORTHERN SOUTH AMERICA... EXPECT DIURNAL CONVECTION
TO OCCUR THROUGH THE NEXT 3-DAYS.
TINOCO...(WPC)
ALAMO...(WPC)
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