182
FXUS63 KGRR 040036
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
835 PM EDT FRI JUL 3 2009
LATEST UPDATE...MARINE...
SYNOPSIS
(409 PM EDT FRI JUL 3 2009)
LOW PRESSURE IN THE PLAINS THIS EVENING WILL SLIDE EAST INTO THE
OHIO VALLEY ON SATURDAY. CLOUDS WILL SPREAD BACK INTO THE AREA LATE
TONIGHT AND KEEP SKIES MOSTLY CLOUDY OVER SOUTHERN LOWER MICHIGAN ON
THE FOURTH FOR A GOOD PORTION OF THE DAY. A FEW RAIN SHOWERS ARE
EVEN POSSIBLE LATE TONIGHT AND ON THE FOURTH ALONG AND SOUTH OF
INTERSTATE 94. HIGH PRESSURE WILL BUILD INTO THE AREA ON SUNDAY
PROVIDING A GOOD DEAL OF SUNSHINE.
SHORT TERM
(409 PM EDT FRI JUL 3 2009)
(TONIGHT THROUGH SUNDAY NIGHT)
WEST NORTHWEST FLOW ALOFT WILL PUSH A SHORTWAVE IN OUR DIRECTION
TONIGHT FROM THE PLAINS...PASSING INTO THE OHIO VALLEY TOMORROW. A
SURFACE LOW WILL MOVE FROM MISSOURI INTO KENTUCKY. THE GRR FORECAST
AREA WILL BE ON THE NORTHERN FRINGES OF THIS SYSTEM WITH CLOUDS
BEING THE MAIN ISSUE. CLOUDS WILL INCREASE FROM THE WEST TONIGHT
AND PUSH THROUGH LOWER MICHIGAN ON SATURDAY. SOUTHERN LOWER MICHIGAN
MAY END UP WITH MOSTLY CLOUDY SKIES THE BULK OF THE DAY. SHOWERS ARE
POSSIBLE...BUT IT APPEARS MOST OF THE RAIN WILL STAY TO OUR SOUTH.
THE I-94 CORRIDOR STANDS THE BEST CHANCE AT SEEING A FEW RAIN
SHOWERS.
CLOUDS SHOULD BE ON THE DECREASE FROM NORTH TO SOUTH SATURDAY NIGHT
AS THE SHORTWAVE AND SURFACE LOW MOVE SOUTH AND EAST OF THE REGION.
SUNDAY SHOULD BE THE MOST SUMMER LIKE DAY OF THE LAST 5...WITH
PLENTY OF SUNSHINE AND TEMPS IN THE UPPER 70S.
AN UPPER LOW WILL DIG INTO THE EASTERN GREAT LAKES REGION SUNDAY
NIGHT INTO MONDAY PUSHING A COLD FRONT INTO THE FORECAST AREA. AT
THIS POINT MOISTURE LOOKS LACKING AND KEPT THE FORECAST DRY.
LONG TERM
(409 PM EDT FRI JUL 3 2009)
(MONDAY THROUGH FRIDAY)
MAIN CONCERN IN THE LONG TERM PORTION OF THE FCST WILL BE
DETERMINING RAIN CHCS THROUGH THE PERIOD WITH FRONTS TRYING TO MOVE
INTO THE AREA. IN ADDITION TO THE RAIN CHANCES...THE DEGREE OF
WARMING WILL HAVE TO BE DETERMINED.
UPPER SYSTEM EXPECTED TO MOVE OUT THIS WEEKEND IS EXPECTED TO BE
REPLACED TO SOME DEGREE BY ADDITIONAL ENERGY DIVING SE OUT OF
CANADA. MODELS ARE DISAGREEING ON THE STRENGTH AND MOVEMENT OF THESE
POTENTIAL FEATURES. THE MODELS DO AGREE WITH KEEPING THE ACTIVE
PORTION OF THE JET NORTH AND EAST OF THE AREA...WHICH SHOULD KEEP
THE PCPN OUT OF THE AREA FOR THE MOST PART THROUGH THU. CHC OF RAIN
IS NOT ZERO...BUT IT IS TOO LOW AT THIS TIME TO MENTION IN THE FCST.
BEST THREAT OF RAIN WOULD BE ON FRI AS A WAVE LOOKS TO BREAK DOWN
THE RIDGE...BUT THERE IS LOW CONFIDENCE EVEN WITH THIS SYSTEM.
UPPER HEIGHTS BUILDING INTO THE AREA AND STRENGTHENING LOW LEVEL SW
FLOW IS EXPECTED TO RESULT IN A WARMING TREND THROUGH THE PERIOD.
ECMWF KEEPS H850 TEMPS A LITTLE COOLER INITIALLY WITH THE UPPER LOW
A LITTLE CLOSER...HOWEVER ALL MODELS WARM H850 TEMPS INTO THE UPPER
TEENS TO AROUND 20C BY NEXT FRI. THIS WOULD SUPPORT TEMPS WELL INTO
THE 80S AND APPROACHING 90...IF NOT WARMER.
AVIATION
(708 PM EDT THU JUL 2 2009)
AS I SUGGESTED YESTERDAY...THE AXIS OF THE POLAR JET MOVED EAST OF
THE GRAND RAPIDS CWA DURING THE MID AFTERNOON TODAY. WITH THAT WENT
THE LOW CLOUD COVER. THUS I EXPECT MOSTLY CLEAR SKIES EARLY TONIGHT.
HOWEVER... THE LEFT ENTRANCE REGION OF THAT SAME JET WILL COME OVER
SOUTHWEST MICHIGAN EARLY SATURDAY MORNING. THAT WILL BRING SOME MID
AND HIGH CLOUDS IN TOWARD MORNING. I BELIEVE THE RAIN WILL STAY
SOUTH OF MICHIGAN WITH THIS EVENT...CLOSER TO I-80 SATURDAY. EVEN
SO... I ALLOWED VCSH IN THE I-94 TAFS FOR THE MID MORNING HOURS OF
SATURDAY. DUE TO THE LAYERED MID AND HIGH CLOUDS I DO NOT BELIEVE
FOG IS MUCH OF A THREAT OVERNIGHT.
MARINE
(835 PM EDT FRI JUL 3 2009)
WILL ADD PATCHY FOG TO THE NEARSHORE WATERS FOR TONIGHT. WEB CAMS
WERE SHOWING FOG ALONG THE SHORELINE AT MUSKEGON AND GRAND HAVEN.
GIVEN THE LIGHT WINDS AND POCKETS OF COOLER WATER THIS FOG IS LIABLE
TO PERSIST IN SPOTS.
OVERALL LIGHT WINDS AND SMALL WAVES ARE EXPECTED THE NEXT 48 HOURS.
A WEAK LOW PRESSURE SYSTEM WILL SLIDE ACROSS THE OHIO VALLEY ON
SATURDAY WITH HIGH PRESSURE IN PLACE NORTH OF THE LOW ACROSS THE
GREAT LAKES. WINDS SHOULD ESSENTIALLY BE 10-12 KNOTS OR LESS THROUGH
SUNDAY EVENING. CORRESPONDINGLY...WAVES SHOULD BE 1-2 FEET OR LESS
THIS WEEKEND. CLOUDS WILL BE FAIRLY PREVALENT ACROSS THE SOUTHERN
HALF OF THE LAKE ON SATURDAY WITH SHOWERS IN THE FAR SOUTH. SUNDAY
SHOULD BE A SUNNIER DAY.
HYDROLOGY
(409 PM EDT FRI JUL 3 2009)
NO HYDROLOGY ISSUES EXPECTED. DRY WEATHER IS EXPECTED FOR MUCH OF
THE NEXT SEVERAL DAYS AND ALL SITES REMAIN WITHIN BANK. ANY RAIN
ACROSS THE SOUTHWEST CORNER OF THE STATE LATE TONIGHT INTO SATURDAY
SHOULD LIGHT.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LM...NONE.
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: NJJ
AVIATION: WDM
MARINE: DUKE JK
HYDROLOGY: DUKE
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