Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 192252
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
652 PM EDT SAT JUL 19 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 321 PM EDT SAT JUL 19 2014

EXCEPT FOR ISOLATED SHOWERS TOWARD JACKSON THROUGH EARLY THIS
EVENING...HIGH PRESSURE WILL DOMINATE THE AREA INTO EARLY NEXT WEEK
AND KEEP THE AREA DRY. THE AREA WILL SEE WARMER AIR GRADUALLY MOVE
INTO THE AREA THROUGH EARLY NEXT WEEK. INLAND LOCATIONS WILL BE
APPROACHING 90 DEGREES FOR HIGH TEMPERATURES ON MONDAY AND TUESDAY
WITH INCREASINGLY HUMID CONDITIONS.

A FRONTAL SYSTEM WILL APPROACH THE AREA ON LATE TUESDAY AND MOVE
THROUGH ON WEDNESDAY. THIS WILL BRING THE NEXT THREAT OF RAIN.
COOLER TEMPERATURES WILL FILTER IN BEHIND THIS SYSTEM LATER NEXT
WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 321 PM EDT SAT JUL 19 2014

THE WEATHER CONTINUES TO LOOK VERY QUIET THROUGH THE SHORT TERM
PORTION OF THE FCST. THE ONLY CHANCE OF RAIN IN THE SHORT TERM WILL
BE EARLY THIS EVENING ACROSS THE FAR SE CORNER OF THE CWFA WHERE
ENOUGH MOISTURE AND THE FAR WRN PERIPHERY OF THE UPPER LOW OVER LAKE
HURON THIS AFTERNOON ARE ALLOWING FOR ISOLATED DIURNAL SHOWERS TO
DEVELOP. THESE ARE EXPECTED TO DISSIPATE BY 00Z THIS EVENING AS THE
UPPER LOW MOVES FAR ENOUGH EAST.

A DRY AND INCREASINGLY WARMER PERIOD IS COMING UP FOR THE REMAINDER
OF THE SHORT TERM THROUGH MON NIGHT. THE STATE WILL BE UNDER THE
INFLUENCE OF THE DOWNSTREAM REGION OF THE BUILDING UPPER RIDGE
ACROSS THE SRN PLAINS TO THE UPPER MS RIVER VALLEY. THIS RIDGE WILL
BUILD AS THE UPPER LOW OVER LAKE HURON DEPARTS AND ANOTHER UPPER
TROUGH MOVES OVER THE PACIFIC NW. SUFFICIENT LOW LEVEL MOISTURE
TRANSPORT FOR PCPN STAYS WELL TO OUR WEST THROUGH MON NIGHT AND
BEYOND.

A SUBSIDENCE INVERSION WILL BE BUILDING AND LOWERING THROUGH THE
PERIOD KEEPING THE DRY CONDITIONS. THE INVERSION JUST BELOW 700 MB
ON SUN WILL ALLOW FOR SOME CU TO BUILD WITH LIMITED VERTICAL HEIGHT.
THE INVERSION BY MON WILL BE LOWER...AND WILL LIKELY KEEP SKIES
MAINLY CLEAR EXCEPT FOR SOME THIN HIGH CLOUDS RIDING OVER THE RIDGE.

WE WILL START OUT WITH TEMPS IN THE LOW TO MID 80S ON SUN AND WARM
TO ALMOST NEAR 90 BY MON. H850 TEMPS WARM A COUPLE OF DEGREES EACH
DAY...AND WILL BE IN THE UPPER TEENS BY MON AFTERNOON. THE AIR MASS
WILL BECOME MORE HUMID EACH DAY AS DEW POINTS INCREASE INTO THE MID
60S BY MON AFTERNOON.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 321 PM EDT SAT JUL 19 2014

A HOT AND HUMID DAY IS EXPECTED TUESDAY. STRONG SOUTH FLOW AHEAD OF
AN APPROACHING COLD FRONT WILL PUSH TEMPS CLOSE TO 90 AND DEWPOINTS
TO AROUND 70. LOW PRESSURE MOVING EAST FROM THE UPPER MISSISSIPPI
VALLEY WILL PROVIDE FOCUS FOR SOME STORM DEVELOPMENT. PWATS CLIMB TO
NEARLY 2.25 INCHES TUESDAY NIGHT AND WEDNESDAY. THUS HEAVY RAINFALL
REMAINS A POSSIBILITY. SHEAR VALUES AROUND 20 KTS SUGGESTS THAT THE
SEVERE POTENTIAL IS LOW DURING THIS TIME.

WE/LL SEE A FEW DAYS OF COOLER AND DRIER AIR AS HIGH PRESSURE BUILDS
IN BEHIND THE COLD FRONT. HIGHS WILL FALL INTO THE 70S FOR THE REST
OF THE PERIOD AS THE COOLER THAN NORMAL WEATHER CONTINUES.

THE STRENGTHENED UPPER LOW OVER THE EASTERN US WILL SEND ANOTHER SFC
LOW TOWARD THE CWA SATURDAY. MORE SHEAR IS PROGD WITH THIS LOW AND
SO THE THREAT FOR STRONGER STORMS IS NOTED SATURDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 652 PM EDT SAT JUL 19 2014

IT WOULD NOW SEEM FOG IS LIKELY OVER THE EASTERN TAF SITES
OVERNIGHT. I COULD EVEN SEE LIFR VSBY AT JXN AND LAN BTW 09Z AND
13Z. THE MORE WESTERN TAF SITES SHOULD REMAIN CLEAR BELOW 12000
AGL TILL CU REDEVELOP BY LATE MORNING SUNDAY.

WHAT WILL CAUSE THE FOG TONIGHT IS A LOW LEVEL EAST TO SOUTHEAST
WIND THAT IS BRINGING HIGHER SURFACE DEW POINT AIR FROM THE VICINITY
OF WESTERN LAKE ERIE NORTHWESTWARD INTO THE JXN AND LAN TAF SITE
AREA DURING THE NIGHT. THE NGMDNG5 AND THE RAP13 MODEL BOTH PICK
UP ON THIS BY SHOWING VSBY DROPPING BELOW A MILE OVER THE EASTERN
1/3 OF LOWER MICHIGAN TONIGHT. MODEL SOUNDING SHOW THE CLASSIC
MERGE OF THE TEMP AND DEW POINT AROUND 09Z AT THE LOWEST LEVELS OF
THE SOUNDINGS. THIS IS NOT SEEN IN THE MKG OR GRR TAF SITES. EVEN
SO I DID LOWER VSBY TO MVFR AT GRR AND IFR TO AZO AND BTL.

THE FOG SHOULD BE QUICK TO MIX OUT SHORTLY AFTER SUNRISE SUNDAY
MORNING AS THE SUN COMES UP AND STARTS TO HEAT THE LOWER LAYERS.
RESULTING IN A LIGHT SOUTHWEST WIND WITH JUST A FEW HIGH BASE
CUMULUS CLOUDS IN THE SKY.

&&

.MARINE...
ISSUED AT 321 PM EDT SAT JUL 19 2014

NO MARINE CONCERNS THROUGH THE WEEKEND...AND LIKELY INTO EARLY NEXT
WEEK. HIGH PRESSURE WILL REMAIN CLOSE ENOUGH TO THE AREA THROUGH THE
WEEKEND TO KEEP THE WEAK GRADIENT IN PLACE. WINDS WILL GENERALLY
REMAIN BELOW 15 KNOTS THROUGH SUN WITH LAKE BREEZES EXPECTED DURING
THE AFTERNOON AND EVENING HOURS.

WINDS WILL INCREASE SOME MON/TUE NEXT WEEK...HOWEVER WE DO NOT
ANTICIPATE HAVING TO ISSUE ANY ADVISORIES UNTIL POSSIBLY FOR TUE
NIGHT AHEAD OF THE NEXT FRONTAL SYSTEM EXPECTED TO COME IN.


&&

.HYDROLOGY...
ISSUED AT 321 PM EDT SAT JUL 19 2014

NO HYDROLOGY ISSUES EXPECTED THROUGH EARLY NEXT WEEK WITH NO RAIN IN
THE FCST UNTIL AT LEAST TUESDAY. RIVER LEVELS/FLOWS RANGE FROM
NORMAL TO MUCH ABOVE NORMAL THIS AFTERNOON...BUT ARE IN THE PROCESS
OF COMING DOWN WITH DRY WEATHER THE LAST COUPLE OF DAYS. MAPLE
RAPIDS IS THE ONLY FLOOD ADVISORY OUT YET. THIS IS JUST BARELY ABOVE
BANKFULL STAGE...AND SHOULD DROP BELOW IT WITHIN THE NEXT 24 HOURS.

&&

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

$$

SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...93
AVIATION...WDM
HYDROLOGY...NJJ
MARINE...NJJ






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