Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 081930
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 PM EDT TUE JUL 8 2014

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

.SYNOPSIS...
ISSUED AT 330 PM EDT TUE JUL 8 2014

UNSEASONABLY COOL WEATHER WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS CAN BE EXPECTED TONIGHT AND WEDNESDAY. HIGH PRESSURE
WILL BRING A BRIEF PERIOD OF QUIET WEATHER THURSDAY INTO FRIDAY
BEFORE SCATTERED THUNDERSTORMS RETURN AGAIN OVER THE WEEKEND ALONG
WITH WARMER AND MORE HUMID.

LOOKING FARTHER OUT... SOME RATHER CHILLY AIR IS FORECAST TO ARRIVE
NEXT WEEK WITH BELOW OR MUCH BELOW NORMAL TEMPERATURES EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM EDT TUE JUL 8 2014

MID LEVEL LONGWAVE TROUGH WILL IMPACT THE GREAT LAKES REGION THROUGH
WEDNESDAY... WITH SEVERAL EMBEDDED SHORTWAVES/VORTICITY MAXIMA
SWINGING THROUGH. THESE FEATURES WILL BRING OCCASIONAL ROUNDS OF
SCATTERED LOW TOPPED CONVECTION.

ONE SUCH SHORTWAVE WAS MOVING ACROSS LK MICHIGAN AT 3 PM AND WILL
LEAD TO SCATTERED SHOWERS AND ISOLATED STORMS LATE THIS
AFTERNOON/EVENING... WITH BEST COVERAGE ALONG AND NORTH OF I-96.

NEXT WAVE WILL DIVE DOWN FROM NRN WI LATE TONIGHT AND WEDNESDAY.
WHILE THE THUNDER THREAT LOOKS LOW ON WEDNESDAY... CAN/T RULE OUT A
FEW ISOLATED STORMS INLAND FROM LAKE MICHIGAN WHERE A FEW HUNDRED
JOULES OF CAPE DEVELOPS.

ANY LINGERING CONVECTION EARLY WEDNESDAY EVENING EXPECTED TO
DIMINISH WITH ARRIVAL OF SFC RIDGE.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 PM EDT TUE JUL 8 2014

TWO MAIN ITEMS TO FOCUS ON IN THE LONG TERM PERIOD. THE FIRST WILL
BE A SHORTWAVE TROUGH THAT WILL BRING COMPLEXES OF STORMS TO THE
MIDWEST THIS WEEKEND AND POTENTIALLY INTO SW LOWER MICHIGAN. THE
SECOND ITEM IS MUCH COOLER WEATHER IN STORE FOR THE MIDDLE OF NEXT
WEEK WITH ABNORMALLY COLD 850 MB TEMPS.

A STRENGTHENING UPPER LEVEL JET MOVING INTO THE UPPER MIDWEST BY
SATURDAY WILL APPROACH 110 KTS AND A CORRESPONDING SHORTWAVE TROUGH
AT 500 MB DIGS INTO THE GREAT LAKES AHEAD OF THIS FEATURE BY 00Z
SAT. A MODEST LLJ OF AROUND 30 TO 35 KTS FORMS AHEAD OF THE SYSTEM
WHICH SHOULD PROVIDE FOR DECENT MOISTURE ADVECTION AT LEAST INTO
IA/WI/IL BUT PROBABLY NOT AS ROBUST INTO SW LOWER MICHIGAN. A
COMPLEX OF STORMS IS EXPECTED TO DEVELOP ON THE WING OF THIS LLJ
ACROSS IA AND HEAD EAST BEFORE WEAKENING OVERNIGHT FRIDAY INTO
SATURDAY LIKELY DUE TO THE SUBSIDING LLJ. THIS IS INDICATED BY
VARIOUS MODEL SOLUTIONS INCLUDING THE EURO...GFS...AND GEM. FOR THAT
REASON WE ARE ONLY CARRYING CHANCE POPS FOR THE EARLY PART OF THE
WEEKEND AND ONLY INCLUDING SHOWER MENTION FOR FRIDAY NIGHT AS
OPPOSED TO THUNDERSTORM WORDING (LACK OF INSTABILITY SHOWING UP ON
GFS BUFKIT SOUNDINGS).

IT APPEARS THAT A 850 MB FRONT AND ASSOCIATED SFC FRONT GET DRAPED
TO THE SOUTH OF THE CWA BY SATURDAY NIGHT AND SUNDAY WITH ADDITIONAL
STORMS FIRING ALONG THE FRONT. THIS ACTIVITY MAY CLIP OUR SOUTHERN
COUNTIES ON SUNDAY. AN ALTERNATIVE SOLUTION SUCH AS THE GEM SUGGESTS
A STRONGER LOW FORMING AND MOVING INTO THE CWA ON SUNDAY WITH A
STRONG COMPLEX OF STORMS. THIS SEEMS TO BE AN OUTLIER SOLUTION AND
WE ARE STICKING WITH CHANCE OR SLIGHT CHANCE POPS UNTIL THERE IS A
CLEARER UNDERSTANDING OF WHERE THE FRONT STALLS OUT. MODEL GUIDANCE
SEEMS TO KEEP MOST OF THE ACTIVITY SOUTH OF OUR CWA.

ATTENTION TURNS TO AN ANOMALOUSLY STRONG AND DEEP UPPER LEVEL
PATTERN MOVING IN BY TUESDAY AND INTO THE REST OF THE MID WEEK
PERIOD. THE EURO IS SHOWING A 130 KT JET CORE DIVING SOUTH OF THE
GREAT LAKES BY TUESDAY AND 500 MB HEIGHTS DROPPING INTO THE 550S DM
WITH AN UPPER LEVEL LOW IN THE MID 540S DM OVER LAKE SUPERIOR. THIS
MAY HELP BRING 850 MB TEMPS CRASHING DOWN INTO THE LOW SINGLE DIGITS
(AT LEAST 1-2 STD DEVS BELOW NORMAL PER GFS ENSEMBLE STANDARDIZED
ANOMALY ANALYSIS) FOR MID WEEK AND IF THIS HOLDS TRUE...WE WILL NOT
GET OUT OF THE 60S BY NEXT WEDNESDAY AND LOWS WILL BE IN THE UPPER
40S TO LOW 50S FOR WHAT IS TYPICALLY THE WARMEST PART OF THE YEAR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 145 PM EDT TUE JUL 8 2014

MONITORING SOME SCATTERED THUNDERSTORMS MOVING ACROSS LAKE
MICHIGAN THIS AFTERNOON. A FEW MAY SURVIVE THE TRIP INTO MKG AND
PERHAPS AS FAR E AS GRR AND AZO. MENTIONED VCSH TO COVER THIS
THREAT WITH THE EXPECTATION THAT MOST OF THE THUNDER ACTIVITY WILL
DECREASE ACROSS THE LAKE. THE OTHER ISSUE TO ADDRESS IS THE
POSSIBILITY OF SOME LOWER CLOUDS AND PERHAPS LIGHT FOG BETWEEN 06Z
AND 12Z. WITH COOLER AIR MOVING IN OVERNIGHT AND FAIRLY LOW
DEWPOINTS EXPECTED BY MID MORNING...IT WOULD SEEM THAT THE THREAT
FOR ANY IFR IS RATHER LOW BUT SOME MODEL GUIDANCE SUGGESTS A
BORDER-LINE THREAT FOR MANY OF THE TERMINALS. WILL HINT AT NEAR
IFR CONDITIONS WITH SCT012 MENTIONED BUT NOT CONFIDENT ENOUGH FOR
BKN OR OVC AT OR BELOW 010.


&&

.MARINE...
ISSUED AT 330 PM EDT TUE JUL 8 2014

WINDS/WAVES EXPECTED TO STAY BELOW SMALL CRAFT ADVISORY TONIGHT
THROUGH AT LEAST THURSDAY.

&&

.HYDROLOGY...
ISSUED AT 330 PM EDT TUE JUL 8 2014

ADDITIONAL AREAL RAINFALL AMOUNTS THIS MORNING WERE GENERALLY AROUND
HALF AN INCH OVER THE HEADWATERS OF THE GRAND AND KALAMAZOO RIVERS.
THIS IS NOT ENOUGH TO SIGNIFICANTLY CHANGE FORECAST CRESTS ALONG THE
MAPLE RIVER AT MAPLE RAPIDS AND THE GRAND AT IONIA. THESE FORECAST
CRESTS ARE ONLY SLIGHTLY ABOVE CURRENT OBSERVED STAGES...SO WILL
STICK WITH THE CURRENT ADVISORIES.

DOWNGRADED THE FLOOD WARNING AT ALMA ON THE PINE RIVER TO AN
ADVISORY. OBSERVATIONS HAVE NOT BEEN AVAILABLE SINCE MONDAY
AFTERNOON. HOWEVER...STAGES WERE ALREADY DECREASING THEN AND
ADDITIONAL PRECIPITATION WAS MARGINAL.

PRECIPITATION WEDNESDAY IS EXPECTED TO STAY WELL UNDER A TENTH OF AN
INCH ON WEDNESDAY. THIS SHOULD HAVE LITTLE IMPACT ON RIVERS AND
ALLOW THEIR OVERALL SUBSIDING TRENDS TO CONTINUE.

&&

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

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...HOVING
AVIATION...HOVING
HYDROLOGY...TJT
MARINE...MEADE









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