Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 041537
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1137 AM EDT MON MAY 4 2015

LATEST UPDATE...
HYDRO

.SYNOPSIS...
ISSUED AT 1117 AM EDT MON MAY 4 2015

FAIR WEATHER IS EXPECTED INTO TONIGHT THEN SOME SHOWERS AND
THUNDERSTORMS WILL RETURN LATE TONIGHT INTO TUESDAY AS LOW
PRESSURE TRACKS ALONG A FRONT STALLED JUST SOUTH OF LOWER
MICHIGAN. MOSTLY FAIR AND WARM WEATHER IS EXPECTED FOR WEDNESDAY
AND THURSDAY WITH SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS
ANOTHER LOW MOVES THROUGH.

&&

.UPDATE...
ISSUED AT 1117 AM EDT MON MAY 4 2015

DROPPED POPS FOR TODAY AND THIS EVENING AS THE FRONT IS THROUGH
AND RADAR TRENDS ALONG WITH THE HRRR SHOWS THE RAIN STAYING SOUTH
OF THE FORECAST AREA INTO THIS EVENING.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 314 AM EDT MON MAY 4 2015

FORECAST CONCERNS DEAL WITH THE EVOLUTION OF THE FRONTAL BOUNDARY
THAT WILL BE MOVING THROUGH THE CWA TODAY. THE FORECAST HASN`T
CHANGED MUCH AND SHOWERS AND STORMS ARE EXPECTED THROUGH WEDNESDAY.

RADAR SHOWS SHOWERS AND EMBEDDED STORMS MOVING ACROSS THE CWA ATTM.
THIS ACTIVITY IS AHEAD OF THE COLD FRONT WHICH IS STILL OVER
WISCONSIN. THE ECHO PATTERN APPEARS AS A PSEUDO WARM FRONT AIDED BY
THE LLJ AIMED AT SW LWR MI. CLOUD TOPS ARE WARMING OVER WISCONSIN
AND WE SHOULD SEE A GENERAL DECREASE IN ECHO INTENSITY TOWARD
MORNING WHEN THE COLD FRONT APPROACHES. HIGHEST POPS THIS AFTERNOON
WILL BE OVER THE SOUTHERN CWA AS THE FRONT MOVES OVER NORTHERN
INDIANA.

WE/LL KEEP SHOWERS/STORMS IN THE GRIDS TONIGHT AS THE ECMWF SHOWS A
WAVE DEVELOPING ON THE BOUNDARY OVER SOUTHERN IOWA AND MOVING EAST.
THE GFS/NAM DON/T REALLY SHOW THE WAVE BUT DO SHOW SOME PCPN NEAR
THE BOUNDARY TUESDAY. THIS BOUNDARY WILL LIFT NORTH IN RESPONSE TO A
DEEPENING PLAINS LOW. TUESDAY WILL BE THE COOLEST DAY OF THE SHORT
TERM WITH HIGHS IN THE 60S. AFTER THE FRONTAL BOUNDARY MOVES
NORTH...TEMPERATURES WILL CLIMB INTO THE 70S WEDNESDAY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 AM EDT MON MAY 4 2015

EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM PERIOD. WHILE
THERE IS SOME THREAT FOR THUNDERSTORMS EACH DAY THE CHANCES SEEM
HIGHEST SATURDAY THROUGH MONDAY.  THERE IS SOME POTENTIAL FOR STRONG
STORMS LATE IN THE WEEKEND INTO EARLY NEXT WEEK.

A CLOSED UPPER LOW OFF THE COAST OF THE STATE OF WASHINGTON AND
SOUTHERN BRITISH COLUMBIA EARLY THIS MORNING DIGS SOUTHEAST INTO THE
SOUTHWESTERN CONUS BY LATE THIS WEEK. THIS BUILDS AN UPPER LEVEL
RIDGE OVER THE EASTERN CONUS THURSDAY INTO FRIDAY. THAT SHOULD FOR
THE MOST PART KEEP THE THREAT OF SHOWERS DOWN AND INCREASE THE
CHANCE FOR HIGHS IN THE LOWER TO MID 80S. THERE IS A SHORTWAVE THAT
TRIES TO COME OUT OF THE WESTERN SYSTEM THURSDAY BUT THE ENERGY FOR
THAT SHOULD MOSTLY BE WEST OF MICHIGAN.  DURING THE WEEKEND A MUCH
MORE POWERFUL PACIFIC SYSTEM BOOTS THE SYSTEM OVER THE SOUTHWEST
INTO THE CENTRAL CONUS BY SUNDAY. IT IS IN THE SUNDAY TO MONDAY TIME
FRAME OUR RISK FOR STRONGER STORMS AND HEAVY RAIN WOULD BE GREATEST.
MODEL AGREEMENT ON THIS IS REASONABLE BUT GIVEN HOW FAR OUT IN TIME
THIS IS... DEALS WILL SURELY CHANGE AS WE GET CLOSER TO NEXT WEEKEND.

MY BOTTOM LINE IS WARM AND MOSTLY DRY THURSDAY AND FRIDAY...SHOWERS
AND THUNDERSTORMS SATURDAY INTO MONDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 626 AM EDT MON MAY 4 2015

ONCE THIS AREA OF CONVECTION AHEAD OF THE COLD FRONT CLEARS THE
AREA BY 12Z OVER THE WESTERN SECTIONS AND 15Z OVER THE EASTERN
SECTIONS THE AREA OF MVFR CIGS CURRENTLY OVER WISCONSIN WILL
FOLLOW FOR TH 13Z TO 16Z TIME FRAME. THAT WILL MOVE OUT OF THE
AREA BY 16Z TO 18Z LEAVING MOSTLY SUNNY SKIES AND A NORTHWEST WIND
AROUND 10 KNOTS FOR THE REMAINDER OF THE DAY. THIS EVENING SHOULD
SEE VFR CONDITIONS CONTINUE THROUGH AROUND 06Z. THEN A WAVE ON THE
FRONT WILL BRING SHOWERS BACK TO THE AREA WITH LOWERING CIG AND
VSBY.


&&

.MARINE...
ISSUED AT 314 AM EDT MON MAY 4 2015

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH
WEDNESDAY. OUTSIDE OF THUNDERSTORMS WINDS AND WAVES WILL BE BELOW
SMALL CRAFT ADVISORY CRITERIA.


&&

.HYDROLOGY...
ISSUED AT 1137 AM EDT MON MAY 4 2015

THE FOCUS WILL BE ON THE ADDITIONAL BOUTS OF RAINFALL POSSIBLE IN
THE WEEK AHEAD.

WHILE THE PATTERN STILL LOOKS ACTIVE IT IS NOT PROMISING THAT WE
WILL SEE ANY WIDESPREAD HEAVY RAIN. BENEFICIAL AMOUNTS SHOULD
AVERAGE OUT TO A QUARTER INCH OR SO WITH EACH EPISODE THROUGH THE
WORK WEEK. THAT MAY LEAD TO DECENT TOTALS IN THE GRAND SCHEME BUT
NOTHING THAT PUTS RIVERS OVER THEIR BANKS.

THE NEXT CHANCE OF RAIN COMES WHEN THE STALLING FRONT TO OUR SOUTH
RETURNS AS A WARM FRONT TUESDAY AND INTO EARLY WEDNESDAY. EVEN
THIS LOOKS TO COME IN A PIECE-WISE FASHION...ONCE LATE TONIGHT AND
AGAIN LATE TUESDAY INTO EARLY WEDNESDAY. THE BEST CHANCE AT RAIN
THEN ENTERS THE PICTURE LATE IN THE WEEK AND INTO NEXT WEEKEND WITH
AN APPROACHING SYSTEM. THIS IS WHEN WE COULD PICK UP OUR HIGHEST
TOTALS...PENDING THE NORTHERN EXTENT OF THE WARM FRONT OUT AHEAD
OF THE SYSTEM. SEVEN DAY TOTALS ON THE ORDER OF AN INCH TO AROUND
AN INCH AND A HALF KEEP CONCERNS LOW AS IT IS RECIEVED IN CHUNKS
WITH SEVERAL HOURS OF DRY TIME BETWEEN. LOCALIZED HEAVIER RAINFALL
CANNOT BE RULED OUT...BUT DURATION AND COVERAGE IS NOT LOOKING
EXTENSIVE AT THIS POINT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...OSTUNO
SYNOPSIS...OSTUNO
SHORT TERM...04
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...JAM
MARINE...04






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