Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 280106
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
906 PM EDT MON APR 27 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 330 PM EDT MON APR 27 2015

HIGH PRESSURE WILL BRING CLEARING SKIES AND DIMINISHING WINDS
TONIGHT... FOLLOWED BY PARTLY TO MOSTLY SKIES FOR TUESDAY. A WEAK
COLD FRONT WILL DROP THROUGH ON WEDNESDAY NIGHT...BRINGING A FEW
LIGHT RAIN SHOWERS AND HALTING ANY WARM UP FROM OCCURRING UNTIL THE
WEEKEND.

&&

.UPDATE...
ISSUED AT 905 PM EDT MON APR 27 2015

AT 0050Z RGNL IR SAT TRENDS SHOW A FAIR AMOUNT OF LOW CLOUD COVER
CONTINUES TO ADVECT IN FROM THE NNE. A CONSENSUS OF 12Z/18Z SHORT
RANGE GUIDANCE PROGS SUGGESTS THAT SOME OF THIS CLOUD COVER WILL
LIKELY LINGER OVERNIGHT ACROSS PORTIONS OF OUR AREA. 12Z MET/MAV
NUMERICAL GUIDANCE NUMBERS GENERALLY SUGGEST MIN TEMPS WILL BOTTOM
OUT IN THE MIDDLE 30S ACROSS MOST OF THE ADVISORY AREA.

GIVEN IR SAT TRENDS AND LATEST NUMERICAL GUIDANCE CONDITIONS FOR
FROST FORMATION LOOK MARGINAL. HOWEVER GIVEN POTENTIAL FOR AT
LEAST SOME PATCHY FROST IN TYPICALLY COLDER LOCATIONS WHERE THE
MOST CLEARING OCCURS WE DECIDED TO LEAVE THE FROST ADVISORY
HEADLINE UNCHANGED.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 330 PM EDT MON APR 27 2015

FIRST ISSUE IN THE SHORT TERM IS FROST POTENTIAL TONIGHT. THE
SURFACE RIDGE CURRENTLY TO OUR WEST WILL BE BUILDING IN WHICH SHOULD
LEAD TO DIMINISHING WINDS AND CLEARING SKIES. THIS CREATES A BETTER
SET UP FOR FROST THAN THE LAST COUPLE NIGHT SO WILL ISSUE A FROST
ADVISORY FOR THE TEN COUNTIES IN SW MI WHERE THE GROWING SEASON HAS
BEGUN.

THE OTHER ISSUE IS THE INCREASING MODEL TREND FOR HAVING ANOTHER
UPPER LOW IMPACT THE AREA WEDNESDAY AND WEDNESDAY NIGHT. THIS
FEATURE DROPS IN AS AN OPEN WAVE FROM THE NORTHWEST ON WEDNESDAY
THEN CLOSES OFF AS IT MOVES SOUTH THROUGH THE AREA WEDNESDAY NIGHT.

DESPITE OUR DRY AIR MASS IT SEEMS REASONABLE TO BELIEVE THAT SOME
SCTD LIGHT RAIN SHOWERS WILL OCCUR WITH THE UPPER LOW WEDNESDAY
AFTERNOON AND NIGHT... ESPECIALLY EAST OF HIGHWAY 131.

THERE WILL ALSO BE A SURFACE COLD FRONT OR TROUGH PASSING THROUGH
WEDNESDAY NIGHT... AND MODELS SHOW H8 TEMPS FALLING TO -2C AGAIN
BEHIND IT. OBVIOUSLY THIS HALTS OUR EXPECTED WARM UP UNTIL THE
WEEKEND.

INBETWEEN OUR DEPARTING UPPER LOW AND THE NEXT ONE... SHORTWAVE
RIDGING IS PROGGED FOR TUESDAY. THIS SHOULD RESULT IN LESS CLOUD
COVER THAN TODAY ALONG WITH LIGHT WINDS AND MILDER TEMPS. HIGHS IN
THE LOWER 60S EXPECTED FOR MOST AREAS ALTHOUGH LAKE BREEZES SHOULD
DEVELOP/STRENGTHEN AT THE COAST IN THE AFTERNOON LEADING TO MUCH
CHILLIER CONDITIONS.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 330 PM EDT MON APR 27 2015

A FAIRLY DEEP UPPER LOW MOVING OVER LAKE MICHIGAN EARLY THURSDAY
WILL REMAIN CLOSE ENOUGH TO THE CWA TO CREATE THE POTENTIAL FOR A
FEW SHOWERS...BUT CONFIDENCE IS LOW ON THAT SINCE THE STRONGEST
DYNAMICS WILL ALREADY BE SOUTHEAST OF OF THE CWA.

A WEAK COLD FRONT IS STILL PROGD TO MOVE ACROSS THE CWA SATURDAY
TOWARD NORTHERN INDIANA AND THEN MOVING NORTH AGAIN SUNDAY. THIS
WILL KEEP LOW CHANCES OF RAIN...BUT PROBABLY NOT THUNDER...IN THE
FORECAST OVER THE WEEKEND. A HIGHER CHANCE OF SHOWERS AND
THUNDERSTORMS WILL COME MONDAY WHEN A STRONGER COLD FRONT APPROACHES
FROM THE WEST. INSTABILITY AND A SOUTHWEST FLOW OF MOISTURE WILL
MOVE OVER THE CWA. WE HAVE THUNDER IN THE GRIDS MONDAY FOR THIS
POTENTIAL.

TEMPERATURES WILL BE MOSTLY IN THE 60S DURING THIS PERIOD BUT PUSH
70 SUNDAY AND MONDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 620 PM EDT MON APR 27 2015

I WOULD EXPECT THE CLEARING TREND WE SEE IN THE VFR BASED CLOUDS
EARLY THIS EVENING WILL CONTINUE THROUGH THE EVENING. ALL OF OUR
TAF SITES SHOULD SEE CLEAR SKIES WITH LIGHT WINDS BY MIDNIGHT.
DAY TIME HEATING WILL BRING CUMULUS CLOUDS BACK INTO THE PICTURE
TUESDAY. VFR CIGS SHOULD BE EXPECTED DURING THE MIDDAY HOURS AT
ALL OR OUR INLAND TAF SITES. WINDS WILL BE LIGHT THROUGH AS
SURFACE HIGH PRESSURE WILL BE MOVING INTO THE AREA. MUSKEGON WILL
SEE A LAKE BREEZE IN THE AFTERNOON AND THAT WILL KEEP THE SKIES
MOSTLY CLEAR THERE.


&&

.MARINE...
ISSUED AT 330 PM EDT MON APR 27 2015

NNW WINDS OF 20-25 KNOTS WILL DIMINISH AND BECOME OFFSHORE LATER
THIS EVENING. UNTIL THEN SMALL CRAFT ADVISORIES REMAIN IN EFFECT.
ANOTHER STRONG NORTH FLOW EVENT... LIKE TODAY AND SUNDAY... LOOKS
LIKELY ON THURSDAY.


&&

.HYDROLOGY...
ISSUED AT 1044 AM EDT MON APR 27 2015

RIVERS ACROSS SOUTHWEST LOWER MICHIGAN ARE AROUND NORMAL LEVELS
AND STEADY OR SLOWLY FALLING. WITH DRY WEATHER FORECAST THIS
WEEK... THESE TRENDS SHOULD CONTINUE THROUGH THE WEEKEND.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 2 AM TO 9 AM EDT TUESDAY FOR MIZ050-056>058-
     064>066-071>073.

LM...NONE.
&&

$$

UPDATE...LAURENS
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...04
AVIATION...WDM
HYDROLOGY...63
MARINE...MEADE






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