Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRR 290728
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
328 AM EDT TUE JUL 29 2014

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

.SYNOPSIS...
ISSUED AT 328 AM EDT TUE JUL 29 2014

A RELATIVELY COOL AND UNSETTLED PERIOD OF WEATHER FOR LATE JULY IS
EXPECTED TO CONTINUE THROUGH MOST OF THE REST OF THIS WEEK. THE AREA
WILL SEE HIGH TEMPERATURES MAINLY IN THE 70S THROUGH THE END OF THE
WEEK. WEAK WAVES OF LOW PRESSURE WILL PASS THROUGH THE AREA THROUGH
THE WEEK. THIS WILL PROVIDE SOME SHOWER AND STORM CHANCES MAINLY
DURING THE AFTERNOON AND EARLY EVENING HOURS. THERE WILL BE MANY
HOURS DURING EACH DAY FOR ANY ONE LOCATION THAT IT WILL NOT BE
RAINING.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 328 AM EDT TUE JUL 29 2014

THE MAIN FOCUS OF THE FCST WILL BE ON THE TRENDS FOR RAIN CHCS EACH
DAY AND WHAT IF ANY SEVERE CHCS WILL BE PRESENT. THE UPPER LOW
CENTERED NEAR HUDSON AND JAMES BAYS WILL REMAIN IN CONTROL OF THE
WEATHER ACROSS THE STATE/REGION. SHORT WAVES WILL CONTINUE TO ROTATE
IN ACROSS THE AREA FROM THE NNW AS WE REMAIN UNDER THE CYCLONIC FLOW
OF THE LOW.

THERE ARE A COUPLE OF LIGHT RAIN SHOWERS NEAR MANISTEE AS OF 07Z
THIS MORNING HEADING TO THE SE. THESE RAIN SHOWERS ARE DIRECTLY
RELATED TO A SHORT WAVE THAT IS COMING IN FROM NRN LAKE MICHIGAN. WE
WILL SEE A FEW SHOWERS REMAIN POSSIBLE THROUGH 12-14Z WITH THIS AS
IT PROGRESSES SE OUT OF THE CWFA BY THAT TIME.

WE WILL THEN SEE THE THREAT FOR SHOWERS AND STORMS INCREASE QUITE A
BIT THIS AFTERNOON. SOME CONVECTION THAT IS ONGOING NW OF LAKE
SUPERIOR EARLY THIS MORNING WITH A SHORT WAVE WILL GRADUALLY SHIFT
SSE INTO THE REGION THIS AFTERNOON DURING PEAK HEATING. HI RES
MODELS ARE INDICATING THAT THE BULK OF THE CONVECTION WITH THIS WAVE
WILL BE ACROSS WI AND CENTRAL AND ERN LOWER MI. THERE CONTINUES TO
BE GOOD AGREEMENT THAT WRLY WINDS WILL LIMIT INSTABILITY IMMEDIATELY
DOWNWIND OF LAKE MICHIGAN AND LIMIT CONVECTION THERE AS A RESULT.

WE AGREE WITH THE SWODY1 FROM SPC THAT THE SEVERE THREAT IS LIMITED
IN OUR NECK OF THE WOODS THIS AFTERNOON. FCST SOUNDINGS INDICATE
RELATIVELY THIN CAPE PROFILES. THIS AND PATTERN RECOGNITION WITH THE
UPPER LOW WOULD POINT TOWARD HAIL OCCURRING WITH THE STORMS...BUT
STAYING SUB-SEVERE WITH CAPE IN THE -10 TO -30C LAYER NOT OVERLY
IMPRESSIVE. WE CAN NOT RULE OUT SOME WIND GUSTS...BUT LIMITED MID
LEVEL WINDS BELOW 40 KNOTS SHOULD KEEP WIND GUSTS SUB-SEVERE ALSO.

AFTER AN EXPECTED LULL IN THE PCPN AFTER EARLY THIS EVENING THROUGH
WED MORNING...ADDITIONAL SHOWERS AND A FEW STORMS WILL BE POSSIBLE
ONCE AGAIN WED AFTERNOON. THE THREAT LOOKS TO BE MORE SE ON WED
AFTERNOON AS A SHORT WAVE AND ASSOCIATED SFC TROUGH ARE OVER THE SE
CORNER OF THE CWFA DURING PEAK HEATING. THE LAKE WILL ALSO LIMIT
INSTABILITY IMMEDIATELY DOWNWIND OF THE LAKE WITH WRLY FLOW AGAIN.
SHORT WAVE RIDGING WILL LIKELY LIMIT CONVECTION A LITTLE ELSEWHERE.
AGAIN. FCST SOUNDINGS INDICATE SOME HAILERS WILL BE LIKELY.

WE WILL REPEAT THE SITUATION ON THU...ALTHOUGH INSTABILITY LOOKS A
LITTLE MORE LIMITED AS TEMPS ALOFT LOOK TO WARM SLIGHTLY. WINDS
ALOFT ALSO DROP OFF A LITTLE...WHICH WILL ALSO LIMIT THE WIND THREAT
A LITTLE MORE.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 328 AM EDT TUE JUL 29 2014

UPPER TROUGHING WILL BE WELL ESTABLISHED AT THE BEGINNING OF THE
LONG TERM (THURSDAY NIGHT) OVER THE EASTERN HALF OF THE LOWER 48.
THE TROUGH WILL BE CENTERED FROM ONT/QUE THROUGH THE GREAT LAKES.
THIS WILL REMAIN THE CASE THROUGH SATURDAY. SUNDAY/MONDAY THE TROUGH
LIFTS OUT SOMEWHAT WITH A GENERAL NORTHWEST FLOW IN PLACE.

AT THE SURFACE VERY WEAK FEATURES TO KEY ON WITH OCCASIONAL TROUGHS
ASSOCIATED WITH MID LEVEL SHORTWAVES MOVING THROUGH. TIMING OF THESE
FEATURES IS SOMEWHAT DIFFICULT AND VARY FROM THE GFS TO THE ECMWF.

AIR MASS WILL HAVE MODIFIED BY THE LONG TERM AND GENERALLY THINKING
HIGHS WILL BE RIGHT NEAR NORMALS FOR THIS TIME OF YEAR...AROUND 80
TO THE LOWER 80S.

SENSIBLE WEATHER WILL FEATURE AFTERNOON AND EVENING SHOWERS AND
STORMS FRIDAY AND SATURDAY AS THE UPPER TROUGH ENHANCES INSTABILITY.
ECMWF BRINGS A FRONT THROUGH THE AREA ON MONDAY OF NEXT WEEK...WHERE
THE GFS IS MORE WRAPPED UP WITH ITS SURFACE LOW AND DELAYS THIS
UNTIL TUESDAY. AT THIS POINT HAVE SMALL POPS...20 PCT IN THE
FORECAST FOR NEXT MONDAY INTO TUESDAY TO PLAY A BIT OF A MIDDLE
GROUND WITH THE FRONTAL PASSAGE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM EDT MON JUL 28 2014

THE CLOUDS ASSOCIATED WITH THE NEXT SYSTEM DROPPING SOUTH INTO
LOWER MICHIGAN ARE COMING IN SLOWER THAN EXPECTED SO I DELAYED THE
ARRIVAL OF THOSE CLOUDS BY A FEW HOURS. THAT MEANS CLEAR SKIES AND
LIGHT WIND MOST OF THE EARLY MORNING HOURS OF TUESDAY.

MODEL SOUNDING LOOK RATHER UNSTABLE FOR TUESDAY DURING THE DAY.
GIVEN THE MOSTLY WESTERLY LOW LEVEL WINDS IT WOULD SEEM THE RISK
FOR THUNDERSTORMS WOULD LARGELY BE WEST OF US-131 SO I DO NOW HAVE
VCTS FOR ALL OF THE TAF SITES EXCEPT GRR AND MKG. I ALSO INCREASE
THE CIGS TO VFR AS MODEL SOUNDINGS SUGGEST CLOUD BASES AROUND 4000
FT AGL. SOME CLEARING IS EXPECTED TUESDAY NIGHT.


&&

.MARINE...
ISSUED AT 328 AM EDT TUE JUL 29 2014

ALL MARINE HEADLINES HAVE NOW BEEN CANCELLED WITH THIS LAST EVENT AS
THE FINAL SOUTHERN ZONE HAS SEEN WAVES DROP DOWN TO AROUND 3 FT AT
THE ST. JOE BUOY. WE WILL SEE A LULL IN THE ACTION THIS MORNING
BEFORE WINDS PICK UP A LITTLE THIS AFTERNOON. WINDS SHOULD COME UP
SHORT OF NEEDING ANOTHER ADVISORY...BUT THIS WILL HAVE TO BE
MONITORED.

&&

.HYDROLOGY...
ISSUED AT 330 PM EDT MON JUL 28 2014

NO HYDRO CONCERNS AT THIS TIME GIVEN ISOLATED TO SCATTERED NATURE OF
THE CONVECTION OVER THE NEXT FEW DAYS. SOME BRIEF LOCALLY HEAVY
DOWNPOURS WITH SMALL HAIL MAY OCCUR EAST OF HIGHWAY 131 AND
ESPECIALLY EAST OF U.S. 127 ON TUESDAY.

&&

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

$$

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





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.