000
FXUS66 KMTR 132354
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
450 PM PDT TUE MAY 13 2008
...RECORD BREAKING HEAT POSSIBLE WEDNESDAY THRU FRIDAY...
.DISCUSSION...AS OF 3:00 PM PDT TUESDAY...SKIES ARE CLEAR ACROSS THE
DISTRICT WITH TEMPS IN THE 60S ALONG THE IMMEDIATE COAST TO THE 70S
AND 80S ELSEWHERE...WHICH ARE ANYWHERE FROM 8 TO 18 DEGREES WARMER
THIS AFTERNOON COMPARED TO YESTERDAY. BUT AS THE SAYING GOES...YOU
AIN'T SEEN NOTHING YET.THE GRADIENT PICTURE SHOWS AN INCREASING
NORTHERLY GRADIENT BETWEEN ARCATA-SFO OF 6.3 MB...WITH THE SFO-SAC
GRADIENT STILL ONSHORE AT 1.7 MB. THE LARGER SCALE SFO-WMC GRADIENT
IS OFFSHORE AT 2.5 MB.
A NEARLY UNPRECEDENTED HEAT EVENT FOR THIS TIME OF YEAR IS IN STORE
FOR THE DISTRICT THE REMAINDER OF THE WORK WEEK. STRONG HIGH PRESSURE
SURFACE AND ALOFT WILL CONTINUE TO STRENGTHEN ACROSS THE DISTRICT.
WINDS WILL INCREASE IN THE HILLS TONIGHT INTO WED MORNING...THE
EVENING SHIFT WILL EVALUATE WEATHER A WIND ADVISORY IS NEEDED. 850 MB
TEMPS WILL CONTINUE TO INCREASE...INCREASING TO NEARLY 24C THURSDAY
AFTERNOON. WITH THE OFFSHORE GRADIENT RAMPING UP EVEN MORE A WIND
ADVISORY HAS BEEN ISSUED FOR THE NORTH AND EAST BAY HILLS WEDNESDAY
NIGHT INTO THURSDAY MORNING. THE COMBINATION OF A 595 DM RIDGE OVER
THE STATE...THE VERY WARM 850 MB TEMPS...AND THE STRONG OFFSHORE FLOW
WILL LEAD TO VERY HOT TEMPERATURES WEDNESDAY AND THURSDAY WITH MANY
RECORDS BEING BROKEN. WEDNESDAY NIGHT/THURSDAY MORNING SHOULD SEE LOW
TEMPERATURES MAINLY IN THE 60S AND LOWER 70S. A VARIETY OF HEAT
ADVISORIES/WARNINGS/WATCHES HAVE BEEN ISSUED. FOR MORE INFORMATION ON
THE HEAT PRODUCTS AND WIND ADVISORY PLEASE SEE SFONPWMTR OR WMO
HEADER WWUS76 KMTR. HOT WEATHER WILL CONTINUE INLAND ON FRIDAY...
WITH A LITTLE COOLING POSSIBLE ALONG THE COAST SINCE THE MODELS INDC
THAT THE WINDS COULD BECOME SOUTHERLY.
THE WEEKEND WILL FEATURE A SLOW COOLING TREND AS THE RIDGE WEAKENS
SLOWLY AND THE FLOW BECOMES A BIT MORE ONSHORE. BY THE EARLY PART
OF NEXT WEEK LOW CLOUDS WILL MAKE A RETURN TO THE COAST AS THE RIDGE
BREAKS DOWN FURTHER.
&&
.AVIATION...AS OF 4:40 PM TUESDAY...VFR CONDITIONS THROUGH
WEDNESDAY. WINDS OF 20-25 KT THROUGH 04Z AT SFO.
$$
.FIRE WEATHER...AS OF 4:50 PM TUESDAY...VERY HOT AND DRY CONDITIONS
ARE FORECAST FOR MUCH OF THE AREA FOR WEDNESDAY THROUGH FRIDAY.
DURING THE DAYTIME...MINIMUM RELATIVE HUMIDITY VALUES MAY DROP TO
SINGLE DIGITS IN MANY INTERIOR SECTIONS ESPECIALLY ON THURSDAY. A
TIGHTER PRESSURE GRADIENT WILL ALSO HELP TO CREATE BREEZY CONDITIONS
WEDNESDAY NIGHT INTO THURSDAY ESPECIALLY OVER THE EAST AND NORTH BAY
HILLS. THE COMBINATION OF HOT TEMPERATURES...LOW RELATIVE
HUMIDITIES...AND BREEZY CONDITIONS WILL MAKE FOR A DANGEROUS FIRE
SITUATION. DUE TO THE FACT THAT FUELS ARE BORDERLINE....FIRE WEATHER
HEADLINES WILL NOT BE ISSUED AT THIS TIME.
$$
.MTR WATCHES/WARNINGS/ADVISORIES...
.WED...EXCESSIVE HEAT WARNING FOR THE SANTA CLARA VALLEY.
.WED...HEAT ADVISORY FOR SAN FRANCISCO AND THE SAN FRANCISCO
BAY SHORELINE.
.THU...EXCESSIVE HEAT WATCH FOR THE ENTIRE SAN FRANCISCO AND
SAN JOSE AREA.
.WED NIGHT THROUGH THU MORNING...WIND ADVISORY FOR THE NORTH
AND EAST BAY HILLS.
$$
PUBLIC FORECAST: MHS
AVIATION/MARINE: MEHLE/W PI
FIRE WEATHER: BELL
NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO
Prepared by Boulder-Creek.com Weather at: Tue May 13 17:30:03 PDT 2008
From the National Weather Service
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