Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 020004
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
804 PM EDT FRI AUG 1 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 115 PM EDT FRI AUG 1 2014

A WEAK AREA OF HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER
THROUGH THE WEEKEND. A FEW AFTERNOON OR EVENING THUNDERSTORMS
COULD POP UP SATURDAY. OVERALL TEMPERATURES WILL BE NEAR TO
SLIGHTLY ABOVE NORMAL. A COLD FRONT WILL PUSH THROUGH THE REGION
BY TUESDAY WITH THUNDERSTORMS POSSIBLE ON MONDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 316 PM EDT FRI AUG 1 2014

THIS EVENING ISOLATED SVR STORM RISK WITH STRONGER CAPE LEADING TO
DEEPER CORES OF REFLECTIVITY. SHEAR IS WEAK. CELLS WILL BE SLOW
MOVERS...GENERALLY AROUND 15 KNOTS. THERE IS ALSO ADDED LIFT FROM AN
APPROACHING SHORTWAVE.  THEY SHOULD WEAKEN AFTER 600 PM AS HEATING
DIMINISHES. WILL GO WITH AN EARLY EVENING PERIOD MENTIONING
POSSIBLE THUNDERSTORMS.

SATURDAY IS SIMILAR TO TODAY MINUS THE LIFT. A FEW STORMS TO
DEVELOP OVER THE INTERIOR AS THE INSTABILITY DEVELOPS. THE CELLS
WILL WEAKEN AS NIGHTFALL APPROACHES AND THE INSTABILITY
DIMINISHES.  WILL KEEP THE LOW POPS GOING FOR THE AFTERNOON.

WARMER AIR ARRIVES AROUND 600 MB FOR SUNDAY. WITH SHOULD ACT TO
LIMIT THE RISK OF ANY STORMS. WILL KEEP IT DRY FOR NOW.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 316 PM EDT FRI AUG 1 2014

A PERSISTENT RIDGE OVER THE ROCKIES WILL RESULT IN A UPPER TROUGH
OVER THE GREAT LAKES NEXT WEEK.

A COLD FRONT WILL MOVE THROUGH THE CWA MONDAY AND WE TSRA IN THE
GRIDS TO COVER THAT. HIGH PRESSURE MOVES OVER LOWER MICHIGAN AFTER
THAT FOR MUCH OF NEXT WEEK...WHICH IS A CHANCE FROM YESTERDAY/S
MODEL RUNS. PREVIOUSLY...THE FRONTAL BOUNDARY WAS REMAINING OVER THE
CWA WHICH NECESSITATED HIGHER POPS ACROSS THE CWA. WE/VE GOT LOWER
POPS NOW UNTIL LATE IN THE WEEK. CAN/T GO COMPLETELY DRY THOUGH AS
NW FLOW ALOFT WILL SEND DOWN SOME SHORT WAVES OVER THE GREAT LAKES.
BUT LOW LEVEL DRY CONDITIONS. THE PLAINS LOW THAT WAS PROGD OVER THE
NRN PLAINS IS NOW PROGD OVER THE CENTRAL PLAINS...WHICH PLACES PCPN
FROM IT OVER ILLINOIS MIDWEEK INSTEAD OF LOWER MICHIGAN. HIGHS WILL
HOLD IN THE 70S THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 803 PM EDT FRI AUG 1 2014

ISOLATED SHOWERS/TSTMS MAY STILL IMPACT THE GRR AND LAN TERMINALS
THROUGH SUNSET. OTHERWISE EXPECT CLEARING SKIES THIS EVENING WITH
SOME FOG/HAZE DEVELOPING OVERNIGHT. THE POTENTIAL DOES EXIST FOR
SOME IFR/LIFR FOG...ESPECIALLY WHERE THE HEAVIER/MORE PERSISTENT
SHOWERS OCCURRED ON FRIDAY AFTERNOON. THE ONLY TERMINAL WHICH HAD
HEAVY RAIN WAS LANSING... SO WENT WITH LOWEST VSBYS BELOW ONE
MILE THERE FROM 09Z-13Z. ELSEWHERE EXPECTING MOSTLY 2-4SM VSBYS
DURING THE LATE NIGHT/EARLY MORNING PERIOD.

SIMILAR TO FRIDAY... ISOLATED SHOWERS/TSTMS SHOULD FORM AGAIN SAT
AFTERNOON AFTER 18Z INLAND FROM LK MI.

&&

.MARINE...
ISSUED AT 316 PM EDT FRI AUG 1 2014

HAZY/LIGHT FOG SITUATION OVER THE LAKE...WILL CONTINUE. WEAK WINDS
SUPPORT LOW WAVE HEIGHTS THROUGH SUNDAY...MOSTLY UNDER 2 FEET.


&&

.HYDROLOGY...
ISSUED AT 115 PM EDT FRI AUG 1 2014

OTHER THAN A COUPLE OF AFTERNOON THUNDERSTORMS THE WEATHER WILL BE
MAINLY DRY. RUNOFF WILL BE LIMITED DUE THE LOCALIZED NATURE OF THE
STORMS. THE ONLY REAL POTENTIAL IMPACT WOULD BE ISOLATED URBAN
FLOODING IF A STORM HAPPENED TO STALL OVER A CITY.

&&

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

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...MEADE
HYDROLOGY...MJS
MARINE...MJS






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