
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
359 AM AST MON JUN 25 2012
.SYNOPSIS...MID-UPPER LEVEL RIDGE PATTERN WILL REMAIN THE DOMINANT WX
FEATURE INTO EARLY NEXT WEEK. A WEAK TROPICAL WAVE WILL MOVE ACROSS
THE AREA ON TUE FOLLOWED BY A SAHARAN AIR LAYER ON WED. A TUTT WILL
REMAIN STRETCHED FROM THE CNTRL ATLC SW INTO THE SRN CARIBBEAN.
&&
.DISCUSSION...DETERMINISTIC AND ENSEMBLE GUIDANCE SHOW HOT AND DRY
WX PATTERN PERSISTING FOR THE NEXT SEVEN DAYS AS AREA REMAINS
UNDER THE INFLUENCE OF STRONG MID-UPPER LEVEL RIDGE AND PERIODIC
SAL EVENTS WITH THE NEXT ONE SCHEDULED TO ARRIVE ON WED BEHIND THE
PASSAGE OF A WEAK TROPICAL WAVE TUE. OTHER THAN AN ISOLD AFTERNOON
TSRA OUT WEST POSSIBLE EACH DAY AND NOCTURNAL SHOWERS ACROSS THE
WATERS MAINLY CARIB WATERS IT JUST LOOKS HOT AND DRY. FCST DOES NOT
HAVE MORE THAN AN ISOLD 20% POP IN ANY GIVEN DAY.
THE MAIN WX CONCERN WILL CONTINUE TO BE FIRE WEATHER ESPECIALLY
GIVEN HOW DRY FUELS ARE RIGHT NOW AND THE FCST OF HOT DRY
CONDITIONS TO PERSIST FOR AT LEAST ANOTHER WEEK. TO ENHANCE THE
FIRE RISK...MODELS SHOW NATLC SFC HIGH STRENGTHENING AFTER WED
WITH SFC RIDGE EXTENDING INTO OUR AREA AND PRES GRADIENT
TIGHTENING. SEE FIRE WEATHER DISCUSSION FOR MORE DETAILS.
&&
.AVIATION...MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS THE
LOCAL TAF SITES FOR THE NEXT 24 HOURS WITH THE EXCEPTION OF TJBQ
BETWEEN 25/18Z AND 25/22Z WHERE VCTS MAY CAUSE MVFR CONDITIONS.
TJSJ 25/00Z SOUNDING INDICATED AN E TO ESE LOW LEVEL WINDS OF 10 TO
30 KTS BTWN SFC TO 15K FEET...BECOMING LIGHT AND VARIABLE 15-30K.
&&
.MARINE...SEAS 3-5 FT AND WINDS UP TO 20 KNOTS. THERE IS A SLIGHT
RISK OF AN ISOLD TSRA MOVING OFF OF THE NW COAST OF PR EACH
AFTERNOON. SOME DUST HAZE IS EXPECTED WED
&&
.FIRE WEATHER...SIG FIRE WEATHER THREAT TODAY DUE TO WINDS AT
20G30MPH AT COASTAL LOCATIONS SIMILAR TO YDAY AND VERY DRY FUELS
ALONG THE NORTH AND SOUTH COAST...ERN HALF OF PR AND THE USVI.
PRECIPITABLE WATER VALUES ARE EXPECTED TO DROP TO NEAR 2SD BELOW
NORMAL TODAY RESULTING IN VERY LOW HUMIDITIES WHEN COMBINED WITH
TEMPS IN THE 90S. 950-850MB LAPSE RATES ARE FCST TO BE QUITE
STEEP TODAY GREATER THAN 7.5C/KM RESULTING IN HIGH LOW LEVEL
INSTABILITY. OVERALL...THE NEXT SEVEN DAYS CONTINUE TO LOOK HOT
AND DRY AND AS DRY AS FUELS ARE ACROSS THE AREA EXPECT EACH DAY TO
HAVE AT LEAST A MODERATE FIRE DANGER THREAT. WINDS WILL ALSO BE
QUITE GUSTY THROUGH WED ENHANCING THE FIRE RISK.
&&
.CLIMATE...YDAY MARKED THE 26TH CONSECUTIVE DAY WITH MAXT AOA
90F AT THE SJU LMM INTL ARPT. THIS NOW RANKS AS THE THIRD LONGEST
STREAK TIED WITH 1981 AND 1982. THE LONGEST STREAK EVER WAS IN 1981
WHEN THERE WERE 35 CONSECUTIVE DAYS. THE MONTH WITH THE MOST 90F DEG
DAYS WAS AUG OF 1982 WHEN THERE WERE 30 DAYS. JUNE 2012 HAS A PRETTY
GOOD SHOT AT TYING THAT RECORD.
SO FAR THIS MONTH THERE HAVE BEEN 9 DAYS WITH MINT AOA 80F. JUNE
2012 IS NOW THE JUNE WITH THE MOST 80F DEG NIGHTS SURPASSING JUNE
1983 WHEN THERE WERE 7 NIGHTS. YDAY MARKED THE 5TH CONSECUTIVE
DAY WITH MINT AOA 80F. THE LONGEST STREAK EVER IS 8 BACK IN OCT
2009.
JUNE 2012 CONTINUES TO BE IN GOOD PACE TO BE THE WARMEST JUNE ON
RECORD AND ALSO THE WARMEST MONTH OF ANY YEAR ON RECORD WARMER THAN
ANY JULY OR AUG WITH AN AVG TEMP SO FAR OF 85.8F DEGS. JUNE 2012 IS
ALSO VERY LIKELY TO END AS THE DRIEST JUNE ON RECORD AND IN THE TOP
FIVE DRIEST MONTHS OF ANY YEAR ON RECORD. THE DRIEST MONTH EVER WAS
MARCH 2005 WHEN ZERO RAINFALL WAS RECORDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 92 79 91 79 / 20 10 10 10
STT 89 80 89 80 / 20 20 20 20