Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 221645
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1245 PM EDT WED APR 22 2015

LATEST UPDATE...
HYDRO

.SYNOPSIS...
ISSUED AT 1056 AM EDT WED APR 22 2015

SCATTERED SNOW SHOWERS WILL CONTINUE THROUGH THURSDAY AFTERNOON.
COLD AIR WILL BRING FREEZING CONDITIONS TONIGHT AND THURSDAY
NIGHT. TEMPERATURES WILL REMAIN BELOW NORMAL INTO NEXT WEEK BUT NO
BIG STORMS ARE EXPECTED.

&&

.UPDATE...
ISSUED AT 1056 AM EDT WED APR 22 2015

LOWERED MAXES A FEW DEGREES AS TEMPERATURES ARE RUNNING COLDER
THAN CURRENTLY FORECAST...WITH CLOUDS AND STRONG COLD ADVECTION
EXPECTED TO LIMIT TEMPERATURE RISES THIS AFTERNOON. ALSO CHANGED
PRECIP TYPE TO ALL SNOW GIVEN CURRENT AND MODEL SOUNDINGS SHOWING
WET BULB ZERO HEIGHTS AT OR NEAR THE GROUND THROUGH TOMORROW.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT WED APR 22 2015

OUR BIGGEST ISSUES IN THE SHORT TERM ARE DEALING WITH PCPN TRENDS
AND TYPE INTO THU...ALONG WITH FROST/FREEZE CONCERNS EACH NIGHT.

SPOTTY SHOWERS...LIKELY BOTH RAIN AND SNOW...CONTINUE TO DRIFT
THROUGH THE AREA THIS MORNING. THE LATEST POSITION OF THE UPPER LOW
HAS IT CENTERED BETWEEN LAKE SUPERIOR AND HUDSON BAY. SPOKES OF
ENERGY CONTINUE TO ROTATE AROUND IT AND PROVIDE THE SHOWERS. THIS
WILL CONTINUE TO BE THE CASE THROUGH THE DAY TODAY. THE DIURNAL
HEATING WILL ONLY ADD TO THE SHOWER ACTIVITY WITH THE COLD POOL
ALOFT NEARBY. WE EXPECT THAT MAINLY SNOW SHOWERS THIS MORNING WILL
TRANSITION TO A MIX OF RAIN/SNOW AS THE BOUNDARY LAYERS WARMS A BIT.

A FEW LEFT OVER SHOWERS THIS EVENING WILL THEN TEND TO DIMINISH IN
COVERAGE OVER THE AREA AS DIURNAL HEATING IS LOST. WE WILL REMAIN
UNDER THE INFLUENCE OF THE CYCLONIC FLOW ALOFT...HOWEVER WE WILL BE
LOSING LOW LEVEL MOISTURE. THIS WILL LEAVE A LOW CHC OF A FEW
RAIN/SNOW SHOWERS THIS EVENING...TRANSITION TO SNOW SHOWERS
OVERNIGHT.

WE EXPECT MORE BREAKS IN THE CLOUD COVER TONIGHT THAT WILL LEAD TO
COLDER TEMPS FOR MUCH OF THE AREA. RECENT COORDINATION WITH LOCAL
AGRICULTURE EXPERTS REVEAL THAT THE GROWING SEASON HAS STARTED FOR
OUR SW CORNER OF THE CWFA. THE BREAKS IN THE CLOUD COVER AND COLD
AIR MASS IN PLACE WILL ALLOW MOST LOCATIONS TO DROP TO OR BELOW
FREEZING TONIGHT. WINDS WILL LIMIT THE AMOUNT OF COOLING A BIT.
AFTER COORDINATION WITH SURROUNDING OFFICES...THE DECISION HAS BEEN
MADE TO HOLD OFF ON FROST/FREEZE HEADLINES FOR NOW AND LET THE DAY
SHIFT RE-EVALUATE THIS TODAY.

THU WILL SEE A MUCH LESS CHC OF ANY PCPN. THE UPPER LOW WILL BE IN
THE PROCESS OF STARTING TO MOVE OUT...AND LOW LEVEL MOISTURE WILL BE
LIMITED. WE HAVE ALLOWED FOR SOME SPRINKLES/FLURRIES BUT THERE
SHOULD NOT BE MUCH MORE THAN THAT ON THU.

THU NIGHT LOOKS LIKE ANOTHER NIGHT OF SOME FROST/FREEZE HEADLINES.
WINDS WILL DECOUPLE BETTER ACROSS THE AREA...AND SKIES SHOULD BE
MAINLY CLEAR WITH THE FLOW ALOFT BECOMING ANTI-CYCLONIC. FRI WILL
SEE A GOOD DEAL OF SUNSHINE IN PLACE WITH RIDGING BUILDING IN ACROSS
THE AREA.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EDT WED APR 22 2015

IT SEEMS THE MAIN PLAYER IN THE LONG TERM PERIOD WILL BE THE DAILY
POSITION OF THE UPPER LEVEL LOW CURRENTLY OVER THE GREAT LAKES
REGION. DESPITE THE FACT THAT IT MOVES OUT AND INTO NEW ENGLAND...
ITS EXPANSIVENESS AND OVERALL PERSISTENCE SHOULD RESULT IN CONTINUED
WEATHER IMPACTS ACROSS THE GREAT LAKES REGION.

THE GENERAL NOTION IS THAT WE TEND TO REMAIN ON THE WRN EDGE OF THE
NEW ENGLAND UPPER LOW THROUGH THE LONG TERM. THE NORTHWEST FLOW
ALOFT HELPS TO SHEAR OUT ANY APPROACHING SYSTEMS AND KEEP THEM
PRIMARILY SOUTH OF MICHIGAN. THE GFS AND ECMWF ARE IN GENERAL
AGREEMENT WITH THIS IDEA FOR THE LATE FRIDAY NIGHT AND SATURDAY
SYSTEM COMING OUT OF THE CENTRAL PLAINS... BUT HAVE VERY DIFFERENT
IDEAS WITH A SYSTEM EMERGING IN THE SRN PLAINS EARLY NEXT WEEK.

BOTH THE GFS AND ECWMF SHOW THE WORST CASE SCENARIO FRIDAY NIGHT AND
SATURDAY BEING SOME LIGHT PRECIPITATION ON THE NRN REACHES OF THE
PLAINS SYSTEM CLIPPING I-94. IF THE PRECIP DOES REACH INTO SRN LWR
MI... IT COULD BE A RAIN/SNOW MIXTURE GIVEN THE COLD/DRY LOW LEVEL
EAST FLOW RELATED TO THE SFC HIGH NORTH OF LK SUPERIOR. ONLY SLGT
CHC POPS AT THIS POINT.

WHILE THE ECMWF SHOWS THE NEW ENGLAND UPPER LOW PERSISTING AND
ACTUALLY RETROGRADING EARLY NEXT WEEK... THE GFS SHOWS A MUCH
FARTHER NORTHEAST SOLUTION. THIS ALLOWS THE GFS TO SEND A WET SYSTEM
OUT OF THE SRN PLAINS AND INTO THE GREAT LAKES FOR NEXT TUESDAY. THE
ECMWF MEANWHILE SENDS THAT SYSTEM EAST ALONG THE GULF COAST WITH DRY
WEATHER AND SFC RIDGING CONTINUING ACROSS MICHIGAN. SINCE THE
CANADIAN AND UKMET SOLUTIONS SUPPORT THE ECMWF... WILL CONSIDER THE
GFS SOLUTION AN OUTLIER AND KEEP IT DRY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 748 AM EDT WED APR 22 2015

GUSTY WEST WINDS AND LOW LEVEL TURBULENCE CAN BE EXPECTED AGAIN
TODAY... ALTHOUGH NOT QUITE AS STRONG AS YESTERDAY. SFC WIND GUSTS
TODAY SHOULD MAX OUT AT 25-30 KTS BEFORE SUBSIDING TONIGHT.

CIGS WILL BE MOSTLY VFR LEVELS AT 3000-5000 FT TODAY BUT THE
SCATTERED SNOW AND RAIN SHOWERS COULD BRIEFLY BRING CIGS OF AROUND
2500 FT AND VSBYS OF 3-6 MILES. SOME ICING IN THE CLOUDS WILL BE
POSSIBLE WHERE THE SHOWERS ARE PRESENT.


&&

.MARINE...
ISSUED AT 330 AM EDT WED APR 22 2015

WE WILL BE HOLDING ON TO THE SMALL CRAFT ADVISORY FOR THE TIME BEING
FOR TODAY. WINDS ALONG THE SHORELINE HAVE DROPPED OFF JUST A
LITTLE...CURRENTLY PRODUCING MARGINAL SMALL CRAFT ADVISORY
CONDITIONS. THIS COULD BE DUE TO SOME SHORT DURATION WEAK WARM AIR
ADVECTION AHEAD OF A WEAK WAVE COMING IN. WE BELIEVE CRITERIA WILL
BE MET AGAIN FOR A GOOD PORTION OF THE DAY TODAY BEFORE DIMINISHING
TONIGHT.


&&

.HYDROLOGY...
ISSUED AT 1245 PM EDT WED APR 22 2015

AS MUCH AS 0.20 TO 0.30 INCHES OF PRECIP FELL ACROSS CENTRAL LOWER
MICHIGAN IN A 24-HOUR PERIOD THROUGH 8 AM THIS MORNING...IN THE
FORM OF BOTH RAIN AND SNOW AT TIMES. A SIGNIFICANT RESPONSE IN
RIVER LEVELS IS CERTAINLY NOT EXPECTED...BUT GRADUAL RISES ARE
ONGOING ON THE PERE MARQUETTE AT SCOTTVILLE. THE WHITE RIVER AT
WHITEHALL IS CURRENTLY ENTERING A CREST.

GOING FORWARD...HYDRO IMPACTS WILL BE MINIMAL. THERE WILL BE A
MUCH LOWER CHANCE FOR ANY PRECIP ON THURSDAY DUE TO LIMITED
MOISTURE. RIDGING BUILDS IN...ALLOWING FOR DRY WEATHER ON FRIDAY.
THERE IS A SLIGHT CHANCE FOR A MIX OF RAIN AND SNOW ACROSS FAR
SOUTHERN LOWER MICHIGAN FRIDAY NIGHT INTO SATURDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ844>849.

&&

$$

UPDATE...OSTUNO
SYNOPSIS...OSTUNO
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...EBW
MARINE...NJJ






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