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000
FXUS63 KGRR 231721
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
121 PM EDT THU MAY 23 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 327 AM EDT THU MAY 23 2013

SHOWERS WILL LINGER THROUGH THE MORNING HOURS...BUT THEN AS DRIER
AIR MOVES IN FROM THE NORTHWEST THE RAINS WILL COME TO AN END
THROUGH THE AFTERNOON AND EARLY EVENING FROM NORTHWEST TO
SOUTHEAST.  AFTER A GLOOMY START TO THE DAY MOST AREAS WILL SEE
SOME SUNSHINE BY LATE AFTERNOON OR EARLY EVENING.  THIS CLEARING
WILL BE THE START OF QUIET PERIOD OF WEATHER WHICH SHOULD LAST
THROUGHOUT THE HOLIDAY WEEKEND.

IT WILL BE MUCH COOLER TODAY WITH HIGHS ONLY 55 TO 60.  PATCHY FROST
WILL BE SEEN TONIGHT NORTH OF I-96.  HOWEVER TEMPERATURES WILL
GRADUALLY REBOUND INTO THE 60S FOR FRIDAY AND SATURDAY...AND MAINLY
INTO THE 70S FOR SUNDAY THROUGH WEDNESDAY.  THE NEXT CHANCE OF RAIN
SHOULD HOLD OFF UNTIL TUESDAY AND TUESDAY NIGHT.

&&

.UPDATE...
ISSUED AT 1212 PM EDT THU MAY 23 2013

COLD FRONT IS SITUATED ACROSS THE FAR SOUTHEAST PORTION OF LOWER
MICHIGAN STRETCHING FROM NEAR THE DETROIT METRO AREA SOUTHWEST
INTO PORTIONS OF NORTHEAST INDIANA. CLOUDS ARE IN PLACE ACROSS THE
ENTIRE FORECAST AREA WITH RAIN SHOWERS LINGERING POST FRONTAL
ACROSS THE BULK OF THE FORECAST AREA YET. HEAVIER SHOWERS AT THIS
POINT CONTINUE FROM THE INTERSTATE 96 CORRIDOR SOUTH...WITH
LIGHTER SHOWERS AND DRIZZLE TO THE NORTH. EXPECT A GRADUAL END OF
THE SHOWERS FROM NORTH TO SOUTH OVER THE COURSE OF THE NEXT 6 TO 8
HOURS...WITH THE BULK OF THE RAIN OVER BY 800PM OR SO. CLOUDS WILL
BEGIN TO CLEAR AS WELL IN THE SAME FASHION...WITH SKIES TURNING
PARTLY CLOUDY IN THE NORTHWEST TOWARD LUDINGTON THIS AFTERNOON.
CLOUDS WILL BEGIN CLEARING OUT DURING THE EVENING FROM HOLLAND TO
ALMA AND IN THE SOUTHERN CWA TOWARDS SUNSET. HIGH TEMPERATURES
WILL BE TEMPERED BY THE CLOUDS AND RAIN WITH MOST SITES SEEING
AFTERNOON HIGHS IN THE UPPER 40S TO MIDDLE 50S.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 327 AM EDT THU MAY 23 2013

A COLD FRONT CUT ACROSS THE CWA THIS MORNING AND IT WILL CONTINUE TO
SAG TO THE SOUTH TODAY.  FGEN BEHIND THE FRONT WAS SUPPORTING A BAND
OF SHOWERS OVER EASTERN WI/LK MI EARLY THIS.  THIS RAIN WILL SWING
THROUGH THE CWA FROM NW TO SE THROUGH THE COURSE OF THE DAY.  UPPER
DYNAMICS WERE ALSO HELPING THIS AREA OF RAIN...AND THE RIGHT
ENTRANCE
REGION OF THE JET WILL SLIDE OVER THE CWA WITH THE RAIN.  SO
NEEDLESS TO SAY THE BAND OF RAIN SHOULD HOLD TOGETHER AND IT LOOKS
WET THROUGH THE MORNING.  THEN THE BACK EDGE OF THE RAIN WILL
GRADUALLY SAG SE THROUGH THE CWA THROUGH THE AFTERNOON AND EARLY
EVENING.  MUCH DRIER AIR MOVES IN AND SKIES WILL CLEAR LATE TODAY.
THIS SHOULD GIVE MOST AREAS A LATE AFTERNOON/EARLY EVENING HIGH TEMP
AS A BIT OF SUNSHINE BOOSTS THE TEMPS UP A BIT.

WILL GO AHEAD WITH A FROST ADVISORY ACROSS THE NORTHERN CWA
TONIGHT.  THIS DOES NOT LOOK LIKE A PROLONG EVENT WITH THE NIGHTS
BEING SO SHORT THIS TIME OF YEAR.  ALSO WITH THE WINDS LIKELY
STAYING UP THROUGH THE EVENING THE ACTUALLY TIME FROST WILL DEVELOP
SHOULD ONLY BE 3 TO 5 HOURS.  LOCALIZED AREAS MAY FALL TO BELOW
FREEZING IN THE NORMALLY COLD LOW SPOTS...BUT THIS SHOULD BE TOO
BRIEF AND TOO ISOLATED TO NEED TO CONSIDER A FREEZE WARNING.

HIGH PRESSURE AND QUIET WEATHER PREVAILS FOR FRIDAY AND SATURDAY.
FROST POTENTIAL APPEAR TO BE LOWER FOR FRIDAY NIGHT GIVEN THAT SOME
MID/HI CLOUDS SHOULD BE MOVING IN ON THE HEELS OF WARM ADVECTION
ALOFT.  WILL MENTION PATCHY FROST FOR NOW AND WILL NEED TO MONITOR
CLOUD TRENDS.  DAYTIME TEMPS WARMING SLIGHTLY EACH DAY.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 327 AM EDT THU MAY 23 2013

A CLASSIC HUDSON BAY HIGH WILL VISIT OUR AREA INTO MONDAY PROVIDING
LITTLE IN THE WAY OF CLOUD COVER AND SLIGHTLY BELOW NORMAL
TEMPERATURES THROUGH MEMORIAL DAY. THIS WILL BLOCK ANY ATTEMPTS OF
SOUTHERN STREAM SHORTWAVES FROM BRINGING ANY CLOUDS AND
PRECIPITATION INTO THE AREA.

BEYOND MEMORIAL DAY THE FORECAST GETS MORE UNCERTAIN. WHILE WE START
OUT WITH AN OMEGA BLOCK TYPE PATTERN (WHICH IS WHY IT SHOULD STAY
MOSTLY CLEAR INTO MEMORIAL DAY) OVER TIME A POWERFUL STORM CURRENTLY
NEAR JAPAN CROSSES THE NORTH PACIFIC GAINING SUPPORT FROM A SYSTEM
IN THE BERING SEA LATE IN THIS WEEKEND. THE SYSTEM REACHES THE WEST
COAST IN THE WEDNESDAY TIME FRAME. NOW THERE ALREADY A SYSTEM
STALLED ALONG THE WEST COAST. WHEN THE JAPAN SYSTEM GETS WEST OF THE
DATELINE... THAT WILL FORCE THE CURRENT SYSTEM INLAND AND THAT WILL
TRY TO FLATTEN THE LARGE RIDGE (1-2 STANDARD DEVIATIONS FROM NORMAL
ON THE 500 MB HEIGHTS) BY MIDWEEK. THAT THEN SETS US UP TO BE IN THE
LINE OF FIRE FOR SHORTWAVES TRAVELING EAST ON THE SOUTHERN STREAM
JET. SO JUST HOW THIS PLAYS OUT IS ANYONE GUESS... SINCE THE
PRIMARY PLAYER IN ALL OF THIS HAS TO CROSS THE PACIFIC OCEAN YET.

SO... ALL THAT BEING SO I HAVE TO ADMIT THERE WILL BE A CHANCE OF
SHOWERS AND THUNDERSTORMS FROM TUESDAY AFTERNOON ON. THUS IN
INCREASED THE POP TO AROUND 30 PCT FROM THEN ON THROUGH THE REST OF
THE FORECAST. WHAT THIS MEANS IS THE FRONT STALLS NEAR US.  ANOTHER
ASPECT TO THIS IS IT SHOULD GET WARM TO HOT AS THE UPPER RIDGE IS
PUSHED EAST A TOUCH MID TO LATE WEEK.  I COULD SEE HIGHS WELL UP
INTO THE 80S FROM WEDNESDAY ON. AGAIN... TIMING SHORTWAVES AND SUCH
WILL BE AN ISSUE WITH THE TEMPERATURES... BUT BOTTOM LINE SUMMER
LIKE WEATHER RETURNS BY WEDNESDAY CONTINUES WELL BEYOND WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 116 PM EDT THU MAY 23 2013

MOISTURE WRAPPING AROUND THE DEPARTING LOW PRESSURE SYSTEM WILL
LEAD TO A FEW HOURS IF IFR WEATHER FROM CLOUDS...FOG AND RAIN TO START
THE 18Z TAFS SOUTH AND EAST OF KGRR. SATELLITE IMAGERY SHOWS RAPID
CLEARING PUSHING SOUTHEASTWARD TOWARD KFKS AND KLDM. THIS WILL BE
THE TREND FOR THE TAF SITES IN SOUTHWEST MI LATER THIS AFTERNOON.
VFR WEATHER TO PREVAIL TONIGHT AND FRI.  MIXING WILL CAUSE SOME
GUSTY WINDS THROUGH 01Z...BUT VALUES SHOULD STAY UNDER 25 KNOTS.

&&

.MARINE...
ISSUED AT 1212 PM EDT THU MAY 23 2013

UPGRADED THE SMALL CRAFT ADVISORY TO A GALE WARNING AS GALES HAVE
BEEN OCCURRING AT THE NORTHERN MARINE OB SITES. FEEL THIS WILL PUSH
SOUTH THIS AFTERNOON AND AFFECT ALL MARINE ZONES WITH TIME. THE
OBS AT MUSKEGON AND HOLLAND MAY NOT SHOW GALES ON LAND...BUT
BELIEVE GALES WILL LIKELY BE ACHIEVED AT THE EDGE OF THE NEARSHORE
ZONE OUT AT 5 MILES. WAVES HAVE ALREADY HIT 11 FEET AT THE
SOUTHERN MID LAKE BUOY.


&&

.FIRE WEATHER...
ISSUED AT 327 AM EDT THU MAY 23 2013

MORE RAIN TODAY WILL KEEP FIRE DANGER LOW.  MUCH DRIER AIR ARRIVES
FOR FRIDAY AND SATURDAY WITH DAYTIME RH VALUES LOWERING TO AROUND 35
PERCENT.  HOWEVER WINDS WILL REMAIN UNDER 10 MPH FOR MUCH OF FRIDAY
AND SATURDAY.

&&

.HYDROLOGY...
ISSUED AT 327 AM EDT THU MAY 23 2013

ADDITIONAL RAIN TODAY WILL BE PERSISTENT...BUT WILL BE ON THE LIGHT
SIDE.  GENERALLY LESS THAN A QUARTER OF INCH IS EXPECTED.  RIVER
LEVELS ARE HIGH WITH ONE ADVISORY VALID FOR THE MUSKEGON RIVER NEAR
CROTON.  RIVER LEVELS SHOULD BEGIN TO SLOWLY FALL LATE TODAY AS THE
BEGINNING OF A DRY SPELL MOVES IN.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 1 AM TO 7 AM EDT FRIDAY FOR MIZ037>040-
     044>046.

LM...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ844>849.

&&

$$

UPDATE...DUKE
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...MJS
FIRE WEATHER...JK
HYDROLOGY...JK
MARINE...DUKE