Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 020742
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
341 AM EDT THU OCT 2 2014

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE

.SYNOPSIS...
ISSUED AT 341 AM EDT THU OCT 2 2014

RAINY WEATHER WITH A ROLLER COASTER TEMPERATURE PATTERN CAN BE
EXPECTED OVER THE NEXT FEW DAYS. A WARM FRONT WILL PUSH NORTH INTO
THE REGION TODAY AND TONIGHT PROVIDING A PERIOD OF MILDER WEATHER.
THEN A STRONG COLD FRONT WILL PASS THROUGH ON FRIDAY BRINGING MUCH
COLDER AIR AND WINDY CONDITIONS BEHIND IT. TEMPERATURES ON SATURDAY
WILL STRUGGLE TO GET OUT OF THE 40S.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 341 AM EDT THU OCT 2 2014

THE HIGHEST POTENTIAL FOR WIDESPREAD RAIN...POSSIBLY HEAVY AT
TIMES... COMES LATE TONIGHT AND FRIDAY MORNING AS THE UPPER TROUGH
EDGES IN FROM THE WEST AND BEST UPPER LEVEL JET DYNAMICS IMPACT THE
AREA. A COUPLED JET STRUCTURE PROVIDES STRONG DIVERGENCE ALOFT
DURING THIS TIME. THIS IS ALSO WHEN THE SFC COLD FRONT... PROCEEDED
BY A 50 KT SOUTHERLY LOW LEVEL JET AND PWATS OVER 1.5 INCHES... WILL
BE SLOWLY MARCHING WEST TO EAST THROUGH LWR MI.

TOTAL RAINFALL AMOUNTS IN EXCESS OF TWO INCHES ARE POSSIBLE MAINLY
WEST OF A LINE FROM BATTLE CREEK TO MOUNT PLEASANT. THIS COULD LEAD
TO SOME NUISANCE FLOODING AND PONDING OF WATER IN LOW AREAS BUT DO
NOT THINK IT IS WORTHY OF A FLOOD WATCH AT THIS TIME.

DESPITE STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS...THE SEVERE
WEATHER THREAT WITH THIS SYSTEM LOOKS QUITE LOW DUE TO LIMITED
INSTABILITY. MU CAPES REALLY STRUGGLE TO EXCEED 700 J/KG THROUGH THE
BULK OF THE EVENT WITH PERHAPS THE EXCEPTION OF THE SW CORNER OF LWR
MI. SFC BASED INSTABILITY OF ANY CONSEQUENCE APPEARS UNLIKELY. CANT
RULE OUT SOME GUSTY SHOWERS AND TSTMS TONIGHT AND EARLY FRIDAY WITH
THE 50 KT LOW LEVEL JET OVERHEAD.

THE RAIN SHOWER POTENTIAL/COVERAGE REMAINS QUITE HIGH FRIDAY NIGHT
AND SATURDAY AS THE UPPER LOW AND COLD AIR IMPACTS THE REGION. LAKE
ENHANCEMENT WILL COME INTO PLAY AS SUB ZERO H8 AIR INVADES THE
REGION BEHIND THE COLD FRONT.

IN THE NEAR TERM... BEST CHANCE OF RAIN TODAY IS THIS MORNING AS
INITIAL BAND OF SHOWERS ON THE LEADING EDGE OF HIGHER PWAT AIR COMES
THROUGH. THERE SHOULD BE A BIT OF LULL THIS AFTERNOON/EVENING...
ESPECIALLY OVER THE ERN CWFA... BETWEEN THIS AREA OF RAIN AND THE
LOW LEVEL JET RAIN LATER TONIGHT.


.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 341 AM EDT THU OCT 2 2014

WE CONTINUE TO EXPECT A COOL AND UNSETTLED WEATHER PATTERN FROM THE
BEGINNING OF THE LONG TERM PERIOD ON SATURDAY NIGHT THROUGH THE DAY
ON TUE. IT DOES LOOK LIKE THIS PATTERN THAT IS MORE TYPICAL OF LATE
FALL SHOULD MOVE OUT LATE IN THE LONG TERM AND WE WILL GET BACK TO
MORE NORMAL EARLY OCTOBER WEATHER.

WE WILL SEE PLENTY OF SHOWER POTENTIAL FROM SAT NIGHT INTO AT LEAST
EARLY SUN. THIS IS WHEN THE MAIN UPPER LOW IS FCST TO MOVE ACROSS
THE AREA ALONG WITH THE CORE OF THE COLD POOL ALOFT. THIS COLD AIR
ALOFT WILL ADD TO THE SHOWER POTENTIAL ALONG THE LAKESHORE WHERE
SUFFICIENT OVER WATER INSTABILITY WILL BE PRESENT /DELTA T/S
APPROACHING 20C/ TO PRODUCE LAKE EFFECT/ENHANCEMENT. THIS COLD AIR
ALOFT WILL ALSO KEEP TEMPS ON SUN IN THE 50S AT BEST.

WE WILL SEE SLIGHT GRADUAL IMPROVEMENT FROM THE SUN AFTERNOON
THROUGH TUE TIME FRAME. THIS OCCURS AS TEMPS ALOFT MODERATE SLIGHTLY
AS THE COLD POOL ALOFT ROTATES OUT OF THE AREA. THE UPPER JET CORE
REMAINS DOES REMAIN SOUTH OF THE AREA. WE WILL GET INTO A PATTERN
THEN WITH INTERVALS OF SHOWERS AS SHORT WAVES MOVE THROUGH THE AREA.
WE WILL ALSO SEE BREAKS IN THE SHOWER ACTIVITY WHEN SHORT WAVE
RIDGING BUILDS IN BETWEEN THE TROUGHS. SFC TEMPS WILL MODERATE A
COUPLE OF DEGREES EACH DAY ON MON AND TUE. TEMPS WILL APPROACH 60
ONCE AGAIN BY TUE.

WE WILL THEN SEE A MARKED IMPROVEMENT FOR THE DAY ON WED. THE LONG
WAVE TROUGH LIFTS OUT OF THE AREA ON TUE NIGHT...AND THE UPPER FLOW
BECOMES ANTI-CYCLONIC BY WED. SOLID WAA THEN TAKES PLACE WITH THE
LOW LEVEL FLOW BECOMING SWRLY. THIS SHOULD GIVE THE AREA AN
OPPORTUNITY TO SEE A GOOD DEAL OF SUNSHINE AGAIN AFTER A CLOUDY
WEEKEND. THE SUN AND MODERATING AIR MASS WILL HELP TEMPS WARM WELL
INTO THE 60S IF NOT APPROACH 70.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 157 AM EDT THU OCT 2 2014

THE MAIN CHALLENGE FOR THE 06Z FCSTS WILL BE PCPN TRENDS OVER THE
NEXT 24 HOURS. THE TERMINALS ARE STARTING OUT WITH ONLY SOME MID
AND HIGH CLOUDS OVERHEAD AS OF 06Z. WE ARE EXPECTING SHOWER
DEVELOPMENT TO THE WEST AFTER 08Z TONIGHT THAT IS EXPECTED TO PUSH
THROUGH THE AREA FROM WEST TO EAST AFTER 10Z. INSTABILITY IS QUITE
WEAK AND THE THREAT OF THUNDER THIS MORNING SEEMS TOO LOW TO
MENTION FOR NOW. THIS WIDESPREAD PCPN IS EXPECTED TO THEN EXIT THE
AREA BY 18Z. WE EXPECT VFR TO MVFR CONDITIONS WITH THIS RAIN.

A FEW SHOWERS OR A STORM WILL BE POSSIBLE THE AFTER 18Z TO ABOUT
03Z. COVERAGE AND CHCS WILL BE LOW ENOUGH THAT A VCSH WILL COVER
THIS POTENTIAL NICELY. MORE WIDESPREAD SHOWERS AND BETTER THUNDER
CHCS WILL COME IN TOWARD 03Z FRI AND MORE LIKELY BEYOND THIS FCST
PERIOD. MVFR WILL DOMINATE EARLY ON IN THIS...AND THE THREAT OF
IFR CONDITIONS WILL INCREASE MORE SO AFTER THE END OF THE FCST
PERIOD.

&&

.MARINE...
ISSUED AT 341 AM EDT THU OCT 2 2014

WILL CANCEL THE SMALL CRAFT ADVISORY NORTH OF GRAND HAVEN WHICH WAS
SLATED TO START AT 5 AM. THE WINDS HAVE A BIT TOO MUCH OF AN
OFFSHORE COMPONENT TODAY. THAT MAY CHANGE AFTER MIDNIGHT TONIGHT
HOWEVER AS THE SOUTHEASTERLY FLOW BECOMES MORE SOUTH SOUTHWESTERLY.

HAVE POSTED A GALE WATCH FOR LATE FRIDAY INTO EARLY SATURDAY FOR THE
WEST NORTHWEST FLOW BEHIND THE STRONG COLD FRONT. WATERSPOUTS ARE
ALSO POSSIBLE IN THE COLD AIR ON SATURDAY AND SUNDAY.

&&

.HYDROLOGY...
ISSUED AT 329 PM EDT WED OCT 1 2014

SOME AREAS COULD PICK UP OVER TWO INCHES OF RAIN THROUGH FRIDAY.
THE HEAVIEST RAINS SHOULD OCCUR THURSDAY NIGHT WITH A FOCUS OVER THE
WESTERN AND NORTHWESTERN CWA.  IT IS POSSIBLE WE WILL SEE NUISANCE
TYPE FLOODING.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WATCH FROM 5 PM FRIDAY THROUGH 10 AM SATURDAY FOR
     LMZ844>849.

&&

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...JK
HYDROLOGY...MEADE
MARINE...MEADE









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