Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 200348
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1148 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM EDT SAT JUL 19 2014

I AM STILL THINKING DENSE FOG IS POSSIBLE AT LANSING AND JACKSON
DUE THE PERSISTENT EASTERLY FEED OF LOW LEVEL MOISTURE FROM LAKE
ERIE AND LAKE HURON. CURRENTLY (0330Z) SURFACE DEW POINTS ARE IN
THE LOWER TO MID 60S OVER THE EXTREME EASTERN PARTS OF LOWER
MICHIGAN. AS THAT AIR IS MIXED WITH THE SURFACE TEMPERATURES
COOLING TO NEAR 60 OVERNIGHT. I HAVE TO IMAGINE FOG WOULD DEVELOP
SINCE WINDS WILL BE LIGHT AND MIXING WILL BE MINIMAL. THIS IDEA OF
FOG IS SUPPORTED BY NEARLY ALL OF THE RUNS OF THE RAP13 MODEL
SINCE SINCE AT LEAST 19TH/21Z. THE 12Z...18Z AND 00Z RUN OF THE
NAM12 SHOW THIS TOO. THE FOG SHOULD MIX OUT QUICKLY AFTER SUNRISE.

AREAS CLOSER TO US-131 WILL HAVE A MORE WESTERLY LOW LEVEL WIND
AND THAT WILL KEEP THE AIR DRIER AND KEEP THE RISK OF FOG AT A
MINIMUM.

SUNDAY DURING THE DAY WILL MOSTLY SUNNY WITH LIGHT WINDS. HIGH
BASED CUMULUS CLOUDS SHOULD DEVELOP BY LATE MORNING BUT A STRONG
SUBSIDENCE INVERSION NEAR 10000 FT AGL SHOULD KEEP THE CLOUDS FROM
GETTING DEEP ENOUGH TO RESULT IN RAIN SHOWERS.

&&

.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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