Area Forecast Discussion
Issued by NWS San Juan, PR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXCA62 TJSJ 230124 AAA
AFDSJU

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
924 PM AST TUE APR 22 2014

.SYNOPSIS...BROAD TROUGH ALOFT OVR THE ATLC WILL PREVAIL THROUGH
EARLY NEXT WEEK AND MAINTAIN ZONAL FLOW. WEAK HIGH PRES WILL BUILD
NORTH OF THE AREA OVR THE WEEKEND.

&&

.DISCUSSION...WHILE OVERALL SFC AND UPPER AIR PATTERN IS ONE OF
BROAD TROUGHING...MODELS INDICATE HEIGHT RISES IN THE ORDER OF
20-30 METERS OVR PR/USVI DURING THE NEXT 24 HRS. THIS WILL LEAD
TO DIABATIC WARMING UNDER SUBSIDING AIR MASS. WARMING WILL ALSO BE
AUGMENTED ON THE NORTH COAST DUE TO COMPRESSIONAL HEATING WITH
DOWNSLOPE FLOW. RECORD HIGHS EXPECTED ONCE AGAIN WED WITH TEMPS IN
THE MID 90S.

A SERIES OF TROUGHS EXITING THE U.S. EAST COAST DURING THE NEXT
SVRL DAYS WILL RESULT IN HEIGHTS FALLING ACROSS THE AREA FRI THRU
EARLY NEXT WEEK BRINGING A RELIEF TO THE HOT WEATHER. A BIT MORE
UNSTABLE AIR MASS WILL ALLOW FOR BETTER CHANCES OF AFTERNOON
CONVECTION INLAND. HOWEVER...ZONAL FLOW ALOFT WILL NOT ALLOW ANY
SIGNIFICANT MOISTURE ADVECTION INTO OUR REGION. SO DRIER THAN
NORMAL CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK. BY MIDDLE
OF NEXT WEEK...OMEGA BLOCK PATTERN IS STRONGLY SUGGESTED BY OP AND
ENSEMBLE GUIDANCE OVR ERN CONUS INTO THE ATLC WITH HIGH AMPLITUDE
RIDGE DEVELOPING BETWEEN 60W AND 70W. THIS IS A SLOW TO EVOLVE
PATTERN WHICH MODELS TEND TO HAVE A FAST BIAS...HOWEVER...
THE 250 MB SPAGHETTI PLOT IS WELL CLUSTERED SUGGESTING HIGH
CONFIDENCE ON PATTERN AND TIMING EVOLUTION. IT APPEARS WELL BELOW
NORMAL RAINFALL IS IN STORE FOR THE NEXT TWO WEEKS.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED ACROSS THE LOCAL FLYING AREA
FOR THE NEXT 24 HOURS. THE 23/00Z TJSJ SOUNDING INDICATED A SOUTH TO
SOUTHWEST WIND FLOW AT 5-15 KT FROM THE SURFACE UP TO 5 KFT.

&&

.MARINE...WINDS 10-15 KT AND SEAS 2-3 FT THRU FRI. WINDS
STRENGTHEN SOME DURING THE WEEKEND WITH SEAS BECOMING 4-6 FT IN
EAST GENERATED WIND WAVES AND MODERATE NORTH SWELLS.

&&

.CLIMATE...RECORD HIGH FOR WED IS ONLY 92F AND TEMPS LIKELY TO
CLIMB AGAIN IN THE MID 90S UNDER SHORTWAVE RIDGE ALOFT AND
SOUTHERLY DOWNSLOPE FLOW.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  92  76  86 /   0   0  10  20
STT  78  85  77  86 /   0  10  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...NONE.
&&

$$

13/64







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.