258
FXUS63 KGRR 071205
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
703 AM EST SAT NOV 7 2009
LATEST UPDATE...ALL SECTIONS EXCEPT AVIATION...
SYNOPSIS
(403 AM EST SAT NOV 7 2009)
IT WILL BE A NICE FALL WEEKEND WITH SOME SUNSHINE EACH DAY AND
DAYTIME TEMPERATURES AROUND 60 TODAY AND INTO THE LOW TO MID 60S ON
SUNDAY. THE NEXT CHANCE OF RAIN WILL HOLD OFF UNTIL MONDAY
AFTERNOON OR EVENING WHEN A COLD FRONT MOVES INTO THE REGION.
SHORT TERM
(403 AM EST SAT NOV 7 2009)
(TODAY THROUGH MONDAY)
MAIN FOCUS WAS ON SKY CONDITIONS AND TEMPS THE NEXT TWO DAYS. THEN
ATTENTION TURNS TO THE CHANCE OF RAIN WITH A COLD FRONT THAT
APPROACHES ON MONDAY.
SATELLITE TRENDS EARLY THIS MORNING POINT TOWARD A MORE OPTIMISTIC
SKY FORECAST FOR TODAY. THERE WERE SOME AREAS OF SC EXTENDING FROM
THE STRAITS DOWN TOWARD MKG...BUT THESE DID NOT LOOK TO IMPRESSIVE.
THE MODEL TRENDS HAS ALSO BACKED OFF ON THE AMOUNT OF LOW CLOUDS
TODAY AS A WEAK COLD FRONT PASSES BY AROUND MID DAY. CAN NOT RULE
OUT A BRIEF PERIOD OF MOSTLY CLOUDY CONDITIONS...BUT FOR THE MOST
PART IT APPEARS WE WILL STAY PARTLY CLOUDY/MOSTLY SUNNY TODAY. WITH
THIS IN MIND TEMPS SHOULD TOP OUT NEAR 60 AT MOST LOCALES...AND A
FEW POCKETS OF MID 60S ARE NOT OUT OF THE QUESTION.
HIGH PRESSURE SETTLES IN TONIGHT BEHIND THE FRONT. SKIES SHOULD
REMAIN MOSTLY CLEAR AND WITH LIGHT WINDS TEMPS WILL DIP TO THE 40 TO
45 DEGREE RANGE. WARM ADVECTION HIGH CLOUDS SHOULD BE ON THE
INCREASE LATE.
A WARM FRONT WILL LIFT NORTH ACROSS THE CWA ON SUNDAY. AS IT
DOES...WE SHOULD SEE CLOUDS THICKEN INTO THE AFTERNOON. EVEN SO...
FEEL WE WILL SEE ENOUGH FILTERED SUNSHINE TO DRIVE TEMPS IN THE MID
60S ACROSS MUCH OF THE CWA. HAVE INCREASED MAX TEMP FORECAST. HAVE
ALSO BUMPED UP MIN TEMPS FOR SUNDAY NIGHT. THE WARM FRONT WILL BE
THROUGH BY THEN AND SOUTHERLY FLOW WILL KEEP TEMPS MILD OVERNIGHT.
IN FACT WE SHOULD SEE STEADY OR SLOWER RISING TEMPS INTO THE WEE
HOURS OF MONDAY MORNING.
HAVE PUSHED THE RAIN CHANCES FOR MONDAY BACK TO THE AFTERNOON ONLY.
THE MODEL TRENDS ARE A BIT SLOWER WITH THE FRONT...STILL HEADING SE
ACROSS NORTHERN LAKE MICHIGAN AT MID DAY...AND TO A OSC-BIV LINE BY
THE END OF THE DAY. THE JET DYNAMICS ARE NOT THAT GREAT WITH THE
FRONT...BUT THE MODELS ARE INDICATING A FAVORABLE POOLING OF
MOISTURE NEAR THE FRONT. WILL CONTINUE CHANCE POPS NW OF A BEH-LAN
LINE. THAT IS AN OUTSIDE CHANCE THERE COULD BE THUNDER ALONG THE
FRONT AS 50 DEGREE DEWPOINTS ADVECTED IN.
LONG TERM
(403 AM EST SAT NOV 7 2009)
(MONDAY NIGHT THROUGH THURSDAY)
PRIMARY CHALLENGE IN THE LONG TERM DEALS WITH THE POTENTIAL FOR
SHOWERS MONDAY NIGHT INTO TUESDAY. GUIDANCE TRENDS SUPPORT PUSHING
THE COLD FRONT SOUTH OF THE INTERSTATE 94 BY 12Z TUE. WILL
THEREFORE KEEP TUE DRY. THE NAM CAME IN RATHER WET FOR MON NIGHT
ALONG WITH SOME ELEVATED INSTABILITY. I CONSIDERED RAISING POPS.
FORECAST SOUNDINGS SHOW CONSIDERABLY MORE MOISTURE IN THE NAM AS
COMPARED TO THE OTHER MODELS. OVERVIEWS FROM THE NAM SHOW ONLY A
NARROW WINDOW FOR SOME DEEPER MOISTURE WITH THE LIFT ELEVATED.
THE GFS IS WEAKER WITH THE LIFT AND THE MOISTURE IS SOMEWHAT
SEPARATED...WHILE THE NEW HIGH RES EURO IS MUCH DRIER THAN EITHER
MODEL. WILL KEEP POPS LOW WITH THIS FRONT AT THIS TIME...GIVEN THE
WEAKER LIFT DOWN LOW AND POTENTIAL FOR THE MOISTURE TO NOT BE
ALIGNED.
GIVEN STRONG HIGH PRESSURE MOVING IN FOR TUE NIGHT INTO WED...I DID
FEATURE LESS IN THE WAY OF CLOUDS.
WITH ONLY A LOW RISK FOR SOME SHOWERS MON NIGHT...THE EXTEND PERIOD
IS LOOKING DRIER THAN NORMAL. DAYTIME HIGH TEMPERATURES WILL END UP
WARMER THAN NORMAL EACH DAY.
AVIATION
(703 AM EST SAT NOV 7 2009)
VFR WEATHER EXPECTED THROUGH TONIGHT. SATELLITE IMAGERY CONTINUES
TO SUGGEST LIMITED CLOUDS THROUGH THE MORNING. INCREASING SUNSHINE
WILL LEAD TO BETTER MIXING AND THUS GUSTY WINDS ARE LIKELY BY NOON.
VALUES OVER 25 KNOTS ARE POSSIBLE. UPON SUNSET...WINDS WILL
DIMINISH.
KEPT THE MENTION OF LLWS FOR A FEW HOURS THIS AM FOR MOST TAF SITES.
40 KNOTS OF WIND AROUND 2000 FT AND RELATIVELY LIGHT WINDS NEAR THE
SURFACE SUGGEST AN INCREASED RISK FOR LLWS.
A WARM FRONT WILL BE DEVELOPING SOUTH OF KAZO TONIGHT AND
WILL MOVE NORTH OF KMKG ON SUNDAY. A RISK FOR SOME LOWER CLOUDS
EXISTS WITH THIS FRONTAL PASSAGE ON SUNDAY.
MARINE
(403 AM EST SAT NOV 7 2009)
BRISK SOUTHWEST WINDS WILL KEEP WAVES HIGH TODAY. HOWEVER ONCE THE
FRONT IS THROUGH AND HIGH PRESSURE BUILDS IN TONIGHT WE WILL SEE A
QUICK CALMING. THE SMALL CRAFT ADVISORY WILL BE MAINTAINED THROUGH
7 PM. SUNDAY APPEARS TO BE A BETTER DAY ON THE LAKE WITH LIGHTER SE
WINDS ONLY PRODUCING WAVES OF 2 FEET OR LESS. WINDS PIVOT TO THE
SOUTH SUNDAY NIGHT AND WAVES SHOULD BEGIN TO BUILD AGAIN.
HYDROLOGY
(403 AM EST SAT NOV 7 2009)
RIVERS WILL CONTINUE TO RECEDE SLOWLY WITH NO SIGNIFICANT RAIN
ANTICIPATED INTO NEXT WEEK.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LM...SMALL CRAFT ADVISORY ST. JOSEPH TO MANISTEE THROUGH 7 PM.
SYNOPSIS: JK
SHORT TERM: JK
LONG TERM: MJS
AVIATION: MJS
MARINE: JK
HYDROLOGY: JK
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