Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 031136
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
736 AM EDT SUN MAY 3 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 337 AM EDT SUN MAY 3 2015

ONE MORE FINE DAY TODAY WITH PARTLY SUNNY SKIES AND TEMPERATURES
REACHING THE UPPER 70S INLAND FROM LAKE MICHIGAN.  THEN A COLD FRONT
APPROACHES TONIGHT AND WILL BRING SHOWERS AND THUNDERSTORMS.  MOST
OF THE PRECIPITATION WILL BE NORTH OF I-96 TONIGHT...THEN SPREAD
INTO SOUTHERN LOWER MICHIGAN ON MONDAY.  THE FRONT MOVES SOUTH INTO
NORTHERN INDIANA BY MONDAY NIGHT AND STALLS THERE.  THIS WILL CAUSE
THE SHOWERS A FEW STORMS TO LINGER MAINLY ALONG AND SOUTH OF I-96
MONDAY NIGHT AND TUESDAY.  MEANWHILE AREAS NORTH OF I-96 SHOULD ONLY
SEE SCATTERED SHOWERS INTO TUESDAY.  DAYTIME TEMPERATURES WILL COOL
SLIGHTLY TO THE UPPER 60S TO AROUND 70 FOR MONDAY AND TUESDAY.

IT APPEARS WE WILL DRY OUT TOWARD MID WEEK...WITH ANOTHER CHANCE OF
STORMS ARRIVING FRIDAY INTO SATURDAY.  DAYTIME HIGHS SHOULD RETURN
INTO THE 70S AND MAY APPROACH 80 THURSDAY AND FRIDAY.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 337 AM EDT SUN MAY 3 2015

ANOTHER VERY NICE SPRING DAY TODAY...THEN RAIN CHANCES RETURN
TONIGHT AND LINGER INTO TUESDAY. SEVERE THREAT STILL LOOKS MINIMAL
AND EXCESSIVE RAIN CHANCES ALSO LOOK REMOTE.

INCREASED MAX TEMPS FORECAST AGAIN DUE TO VERY DRY AIR MASS AND
FAVORABLE MIXING.  FEEL UPPER 70S WILL BE COMMON AND AN ISOLATED 80
IS NOT OUT OF THE QUESTION.  WE SHOULD SEE A FEW SOME DEBRIS CLOUDS
ROLL IN BY MID AFTERNOON WHICH TAPER THE MIXING AND HEATING AFTER
18Z.

A COLD FRONT MOVING ACROSS MN THIS MORNING WILL REACH SOUTHWEST MI
ON MONDAY.  THE FRONT WILL HAVE FAVORABLE JET DYNAMICS TO OUR WEST
LATER THIS AFTERNOON AND EXPECT WIDESPREAD PCPN SPREADING ACROSS
WISCONSIN.  THE UPPER JET BRINGS IN WEAK UPPER DIVERGENCE INTO THE
NW CWA TONIGHT.  SO SOME OF THE WISCONSIN CONVECTION SHOULD HOLD
TOGETHER AND MOVE INTO CENTRAL LOWER TONIGHT.  EXPECTING OF THIS
ACTIVITY TO REMAIN NORTH OF I-96 AS AREAS SOUTH OF THERE WILL BE TOO
FAR REMOVED FROM THE UPPER JET.  SO GENERALLY WILL CARRY LIKELY POPS
NORTH AND CHC POPS SOUTH OF I-96.

THE SHOWERS AND STORMS GRADUALLY SHIFT SOUTH ON MONDAY AS THE FRONT
COMES THROUGH.  DECENT INSTABILITY COULD BE REALIZED SOUTH OF I-96
BY AFTERNOON WHERE WE MAY SEE AN ISOLATED STRONGER STORM...BUT THIS
WILL DEPEND ON THE EXTENT OF THE MORNING CLOUD COVER.  THE FORCING
DOES NOT LOOK STRONG ENOUGH TO BE TOO CONCERNED THOUGH...AS THE
FRONT BECOMES MORE PARALLEL TO THE UPPER FLOW.

THE FRONT MOVES THROUGH BY MONDAY EVENING AND STALLS OVER NORTHERN
INDIANA MONDAY NIGHT AND TUESDAY.  DECENT OVER RUNNING FORCING IS
SHOWN FOR AREAS SOUTH OF I-96...SO THE SHOWERS SHOULD CONTINUE WITH
A FEW EMBEDDED STORMS.

THE CONVECTIVE NATURE OF THE PCPN COULD LEAD LOCALIZED HEAVY
RAIN...BUT OVERALL EXPECT AROUND A QUARTER INCH FOR CENTRAL...AND UP
TO THREE QUARTER OF AN INCH FOR THE I-94 REGION THROUGH TUESDAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM EDT SUN MAY 3 2015

PRIMARY FOCUS IS ON THE CHANCE FOR SCATTERED SHOWERS/STORMS TUESDAY
NIGHT AND WEDNESDAY AND ALSO THE DEGREE OF WARMTH FOR THURSDAY AND
FRIDAY.

STATIONARY BOUNDARY ACROSS FAR SOUTHERN LOWER MI TUESDAY NIGHT
BEGINS LIFTING NORTH AS A WARM FRONT WITH UPPER LEVEL RIDGE
AMPLIFICATION OCCURRING ACROSS THE OHIO VALLEY AND GREAT LAKES
REGIONS. THIS FRONT WILL SERVE AS A SOURCE OF LIFT AND PROVIDE
OPPORTUNITY FOR SOME SCATTERED SHOWER/STORM DEVELOPMENT COINCIDENT
WITH RISING DEW POINTS INTO THE UPPER 50S/NEAR 60 ON WEDNESDAY.
MODEL QPF IS NOT OVERLY BULLISH ON WEDNESDAY...BUT WOULD EXPECT SOME
CONVECTIVE DEVELOPMENT AFTER MORNING H925 TEMP INVERSION IS MIXED
OUT AND SFC BASED CAPE OF A FEW HUNDRED JOULES/KG ARE REALIZED ALONG
WITH LI VALUES SLIGHTLY NEGATIVE. THAT SAID...WITH WINDS AT OR BELOW
20 KTS FROM THE LCL TO THE EL AND MARGINAL CAPE IN THE -10C TO -20C
LAYER...THERE IS NO REAL THREAT FOR SEVERE WEATHER.

BY THURSDAY...MOSTLY DRY CONDITIONS ARE EXPECTED WITH A FEW STRAY
SHOWERS OR STORMS POSSIBLE...BUT WITH A LACK OF ANY TRIGGER VERY
LITTLE CONVECTIVE ACTIVITY IS FORESEEN. H850 TEMPS OF 13C BY 00Z FRI
SUPPORT HIGHS AROUND 80. FOR FRIDAY...A SFC COLD FRONT SHOULD BE
PUSHING THROUGH WISCONSIN DURING THE AFTERNOON HOURS...AND WE MAY
HAVE A CHANCE TO MIX DOWN 14C AIR...WHICH WOULD SUPPORT HIGHS IN THE
LOWER 80S. GIVEN INCREASING CLOUD COVER AND POSSIBLE SHOWER/STORM
DEVELOPMENT AHEAD OF THIS FRONT...WE MAY NOT QUITE GET THERE BUT IT
IS STILL A DECENT POSSIBILITY. FOR NEXT WEEKEND...NEED TO CONTINUE
THE MENTION FOR SHOWER/STORM POSSIBILITIES AS UPPER LEVEL RIDGING
MAY RELAX SOMEWHAT BUT WITH CONTINUED MOIST LOW LEVEL FLOW AND
POSSIBLE SFC BOUNDARY IN PLAY ONCE AGAIN ACROSS THE GREAT LAKES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN MAY 3 2015

INCREASING MID LEVEL CLOUDS TODAY WITH VFR CONDITIONS BUT
INCREASING SW BREEZE. A FEW POCKETS OF LIGHT SHOWERS COULD AFFECT
ANY OF THE TAF SITES DURING THE MID TO LATE AFTERNOON HOURS...BUT
MORE LIKELY THAT ANY SHOWERS/STORMS WILL HOLD OFF UNTIL EARLY
MONDAY MORNING AS A LINE OF THUNDERSTORMS FROM WISCONSIN SHOULD
MOVE OVER LAKE MICHIGAN AND WEAKEN PRIOR TO SUNRISE MONDAY.

BEYOND 12Z MONDAY...ADDITIONAL SHOWERS/STORMS ARE POSSIBLE JUST
ABOUT ANYWHERE BUT ESPECIALLY FOR AZO/BTL/JXN MONDAY
AFTERNOON/EVE...WITH ACTIVITY LIKELY PRESSING INTO NORTHERN
INDIANA AND OHIO BY LATE IN THE DAY.


&&

.MARINE...
ISSUED AT 337 AM EDT SUN MAY 3 2015

SOUTH WINDS WILL CAUSE WAVES TO INCREASE THIS AFTERNOON MAINLY NORTH
OF HOLLAND.  EXPECT SOME 3 FOOTERS...BUT OVERALL A SMALL CRAFT
ADVISORY IS NOT EXPECTED TO BE NEEDED.  THESE WAVES WILL DIMINISH
LATE TONIGHT/EARLY MONDAY AS THE FRONT MOVES IN.


&&

.FIRE WEATHER...
ISSUED AT 337 AM EDT SUN MAY 3 2015

WITH TEMPS INTO THE UPPER 70S AND A DRY AIR MASS...THE FIRE DANGER
WILL BE AT ELEVATED LEVELS TODAY.  HOWEVER WINDS ARE NOT EXPECTED TO
BE TOO HIGH TODAY...GENERALLY REMAINING UNDER 15 MPH.

&&

.HYDROLOGY...
ISSUED AT 250 PM EDT SAT MAY 2 2015

RIVERS MAY RISE A BIT BY THE MIDDLE OF NEXT WEEK AS AS ABOUT AN
INCH OF QPF IS POSSIBLE BY NEXT WEDNESDAY. SINCE RIVER LEVELS ARE
RUNNING A BIT BELOW AVERAGE...THIS SHOULD NOT CAUSE MANY IMPACTS.

&&

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

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...HOVING
AVIATION...HOVING
FIRE WEATHER...JK
HYDROLOGY...OSTUNO
MARINE...JK





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