Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 211930
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 PM EDT THU AUG 21 2014

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

.SYNOPSIS...
ISSUED AT 330 PM EDT THU AUG 21 2014

VERY WARM AND HUMID CONDITIONS WILL PREVAIL FOR THE NEXT SEVERAL
DAYS. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TONIGHT BUT
ONLY ISOLATED SHOWERS AND STORMS ARE EXPECTED FROM FRIDAY THROUGH
THE WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 330 PM EDT THU AUG 21 2014

CONFIDENCE IS STILL TOO LOW TO ISSUE A FLOOD WATCH FOR TONIGHT.
LATEST MODEL GUIDANCE TRENDS ARE TO SHIFT THE AXIS OF HEAVIEST RAIN
TONIGHT A BIT FARTHER SOUTH.

PREVIOUS GUIDANCE HAD BEEN FOCUSING THE BEST QPF FROM MILWAUKEE TO
KALAMAZOO... BUT NOW IT LOOKS MORE LIKE CHICAGO TO SOUTH BEND. THIS
MAKES SENSE BASED ON THE LOW LEVEL JET PROGS WHICH SHOW A SOUTHWEST
FLOW AIMED TOWARD SW LWR MI THIS EVENING BUT THEN INDICATE IT
VEERING WESTERLY OVERNIGHT. THE SEVERE WEATHER THREAT HAS SHIFTED A
TAD FARTHER SOUTH AS WELL TO THE CHICAGO TO SOUTH BEND CORRIDOR
WHERE BEST INSTABILITY AND WARM FRONT WILL BE.

HOWEVER BASED ON INCONSISTENT MODEL QPF AND LLJ SOLUTIONS FOR
TONIGHT OVER THE LAST FEW RUNS... STILL CANT TOTALLY RULE OUT
LOCALLY HEAVY RAIN/FLOODING OVER THE SW CWFA CORNER OF THE CWFA
TONIGHT. ALSO OF CONCERN IS THE PRESENCE OF RIGHT ENTRANCE REGION
LIFT RELATED TO NW TO SE ORIENTED JETLET OVER LK HURON.

IN THE SHORT TERM... INCREASED POPS CONSIDERABLY FOR THE REST OF
TODAY AS WIDESPREAD RAIN FROM DECAYING WI MCS MOVES EAST.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU AUG 21 2014

THE LONG TERM PORTION OF THE FCST LOOKS TO BE RATHER WARM THROUGH A
GOOD PORTION OF THE PERIOD AND FAIRLY UNSETTLED WITH CHCS OF PCPN
EACH DAY THROUGH THE PERIOD.

THE LOWEST THREAT OF RAIN LOOKS TO BE AT THE BEGINNING OF THE PERIOD
ON SUN. THIS IS WHEN THE UPPER RIDGE BUILDS OVERHEAD AS THE UPPER
LOW TAKES SHAPE ACROSS THE ROCKIES. THE CORE OF THE HOT AIR SHOULD
BE JUST WEST OF THE AREA...HOWEVER IT STILL LOOKS VERY WARM AND
HUMID ON SUN. FCST SOUNDINGS SHOW A FAIRLY SUBSTANTIAL CAP BETWEEN
5-10K FT THAT SHOULD KEEP MOST AREAS DRY. WE CAN NOT RULE OUT AN
ISOLATED STORM ALONG SOME SORT OF BOUNDARY LIKE A LAKE BREEZE WITH A
GOOD DEAL OF INSTABILITY PRESENT.

THE CHC OF SHOWERS AND STORMS WILL THEN INCREASE A BIT ON MON AND
REMAIN POSSIBLE THROUGH THE END OF THE PERIOD ON THU. THE ROCKIES
LOW WILL LIFT NE...REMAINING NORTH OF LAKE SUPERIOR. THIS WILL HELP
TO FLATTEN THE RIDGE OVER THE AREA...AND ALLOW THE COLD FRONT TO
SINK SOUTH INTO THE AREA BY TUE. THE WARMEST DAY LOOKS TO BE ON MON
WHERE 90 DEGREES WILL BE POSSIBLE. THE FRONT LOOKS TO STALL OUT OVER
THE SRN PORTION OF THE AREA ON TUE. THE MODELS ARE NOW SHOWING
ADDITIONAL ENERGY COMING IN FROM THE WEST MID WEEK HELPING TO KEEP
THE FRONT ACTIVE. THIS WILL KEEP THE CHC OF SHOWERS/STORMS IN FOR
THE AREA THROUGH THE END OF THE PERIOD. TEMPS WILL COOL A BIT WITH
THE LOWER HEIGHTS AND MORE PCPN POTENTIALLY AROUND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 156 PM EDT THU AUG 21 2014

THE NEXT 24 HOURS WILL BE QUITE UNSETTLED...ESPECIALLY FOR
TERMINALS THAT ARE FURTHER SOUTH AND WEST. AN AREAS OF SHOWERS AND
ISOLATED STORMS ACROSS WISCONSIN IS TRYING TO MAKE THEIR WAY
ACROSS LAKE MICHIGAN. THEY ARE WEAKENING AS EXPECTED...HOWEVER
THEY COULD STILL IMPACT WRN TERMINALS THROUGH ABOUT 22Z OR SO.
CONDITIONS ARE MAINLY MVFR AND ABOVE...HOWEVER THERE IS SOME
ISOLATED IFR THAT CAN NOT BE RULED OUT. THIS MAY COMPLETELY
DISSIPATE BY THE TIME IT WERE TO REACH THE ERN TERMINALS.

WE EXPECT THAT THERE WILL BE A LULL OF A FEW HOURS MID
EVENING...BEFORE ANOTHER COMPLEX OF STORMS WILL POTENTIALLY
DEVELOP. THE BIGGEST POTENTIAL IMPACT FROM THESE STORMS WILL BE
FOUND TOWARD KBTL AND KAZO...HOWEVER THE OTHER TERMINALS COULD BE
IMPACTED DEPENDING ON WHERE AND WHEN THE STORMS DEVELOP WHICH IS
STILL A LITTLE UNCERTAIN. THESE STORMS WHERE EVER THEY DEVELOP AND
MOVE THROUGH SHOULD CONTAIN QUITE A BIT OF IFR. THESE STORMS
SHOULD EXIT THE SE PORTION OF THE AREA BY 12Z OR SO. CONDITIONS
SHOULD THEN QUIET DOWN THEREAFTER THROUGH THE REMAINDER OF THIS
FCST PERIOD.


&&

.MARINE...
ISSUED AT 330 PM EDT THU AUG 21 2014

MINIMAL WIND AND WAVE ACTION IS EXPECTED THE REST OF THIS WEEK
THROUGH THE WEEKEND. HOWEVER AREAS OF DENSE FOG WILL POSE A HAZARD
TO MARINERS DUE TO A VERY WARM AND HUMID AIRMASS OVERRUNNING
RELATIVELY COOL LAKE WATER.

&&

.HYDROLOGY...
ISSUED AT 330 PM EDT THU AUG 21 2014

GIVEN THE LATEST LOW LEVEL JET PROGS AND GUIDANCE PLACEMENT OF BEST
QPF MAINLY SOUTH OF MI... THE FLOOD THREAT SEEMS TO BE LOWER THAN
PREVIOUS THOUGHT. WILL NOT ISSUE A FLOOD WATCH BUT SOME AMOUNTS IN
EXCESS OF TWO INCHES CANNOT BE COMPLETELY RULED OUT SW OF GRR.

&&

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

$$

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








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