Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | 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 281803
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
203 PM EDT TUE JUL 28 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT TUE JUL 28 2015

ANOTHER SUNNY AND HOT DAY WITH TEMPERATURES NEAR 90 CAN BE
EXPECTED BEFORE A COLD FRONT BRINGS A PERIOD OF CLOUDS WITH
SCATTERED SHOWERS AND THUNDERSTORMS LATE TONIGHT AND WEDNESDAY.
SLIGHTLY COOLER AND LESS HUMID WEATHER WILL FOLLOW BEHIND THE
FRONT ON THURSDAY ALONG WITH PLENTY OF SUNSHINE.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 330 AM EDT TUE JUL 28 2015

THE MAIN FOCUS IS ON PRECIPITATION POTENTIAL WITH THE INCOMING FRONT
LATE TONIGHT AND WEDNESDAY AS WELL AS THE CHANCE FOR A FEW STRONGER
STORMS. IT HAS BEEN OVER A WEEK NOW WITH ANY SUBSTANTIAL RAINFALL SO
WE COULD USE SOME RAIN.

UNFORTUNATELY THIS SYSTEM DOES NOT APPEAR TO HAVE MUCH TO OFFER IN
TERMS OF AREAL COVERAGE OF HEAVIER RAINFALL AMOUNTS. THE SHOWERS
WILL BE SCATTERED AT BEST AND MOST LOCATIONS WILL SEE LESS THAN ONE
QUARTER INCH OF RAIN. THAT SAID THE PRECIPITABLE WATER VALUES ALONG
AND AHEAD OF THE FRONT WILL BE NEAR TWO INCHES WHICH DOES SUPPORT
THE POSSIBILITY OF SOME LOCALIZED HEAVY DOWNPOURS.

UPPER SUPPORT WILL BE SERIOUSLY LACKING WITH THIS SYSTEM AS THE MID
LEVEL SHORTWAVE PASSES WELL TO OUR NORTHWEST... TRACKING FROM THE
NRN PLAINS NORTHEAST TOWARD HUDSON BAY. THIS RESULTS IN DEEP LAYER
SHEAR VALUES OF LESS THAN 20 KTS...GREATLY LIMITING THE POTENTIAL
FOR ANY ORGANIZED SEVERE STORMS.

THE THING TO WATCH WILL BE EXTENT OF DESTABILIZATION WEDNESDAY
BEFORE FROPA AS MU CAPE PROGS SHOW NEAR 2000 J/KG SOUTH AND EAST OF
GRR WEDNESDAY AFTERNOON. THIS COULD SUPPORT A FEW ISOLATED STRONGER
STORMS AROUND JXN BEFORE DEVELOPING LOW LEVEL WESTERLY FLOW PUSHES
CONVECTION COMPLETELY OUT OF THE AREA.

EXPECT HIGH TEMPS TODAY VERY SIMILAR TO YESTERDAY WITH UPPER
RIDGE/SUBSIDENCE STILL FIRMLY IN PLACE AND LIMITED CLOUD COVER. THE
LAKESHORE SHOULD BE AS WARM OR WARMER THAN INLAND AREAS AGAIN WITH
SOUTHEAST LOW LEVEL FLOW. A WEAK LAKE BREEZE IS EXPECTED TO DEVELOP
THIS AFTERNOON WHICH SHOULD COOL THE BEACHES A BIT.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 AM EDT TUE JUL 28 2015

THE TREND FOR THE LONG TERM OVER THE PAST 24 HOURS IS FOR A DELAY IN
SOLID PCPN CHCS TO SAT NIGHT AND BEYOND.

THE CHC OF RAIN FOR FRI IS NOT ZERO...HOWEVER IT LOOKS TO BE LOW
ENOUGH TO LEAVE OUT OF THE FCST FOR THE TIME BEING. A WEAK FRONT
DOES LOOK TO DROP THROUGH THE FCST AREA DURING THE DAY ON FRI AS
UPPER TROUGHING BEGINS TO TAKE A BETTER HOLD ON THE AREA. THE ISSUE
WITH PCPN WITH THIS FRONT IS THAT THE UPPER ENERGY STAYS NORTH OF
THE AREA...AND THERE IS LITTLE MOISTURE RETURN WITH THE LOW LEVEL
FLOW FROM THE W/NW. THE WRLY FLOW WILL ALSO LIMIT PCPN CHCS BEING
DOWNWIND OF THE COOLER WATERS OF LAKE MICHIGAN.

SAT LOOKS TO BE DRY ACROSS THE AREA NOW WITH THE WEAK FRONT COMING
THROUGH ON FRI AND THE NEXT SYSTEM NOT EXPECTED TO ARRIVE UNTIL SAT
NIGHT/SUN. TEMPS DO NOT LOOK TO BE THAT MUCH COOLER ON SAT BEHIND
THE FRONT. H850 TEMPS DROP ONLY A COUPLE OF DEGREES AND REMAIN IN
THE MID TEENS. THIS WILL CONTINUE TO SUPPORT HIGHS IN THE 80S.

SUN AND MON DO CONTINUE TO LOOK SOMEWHAT UNSETTLED WITH OCCASIONAL
CHCS FOR RAIN EACH OF THE DAYS. THERE IS A LITTLE BETTER CHC THAT WE
WILL SEE WAVES CLOSE ENOUGH TO GIVE PCPN CHCS A BOOST. IN
ADDITION...THERE LOOKS TO BE A BETTER SURGE OF MOISTURE COMING IN
FROM THE GULF OF MEXICO. WE COULD BE LOOKING AT SOME POTENTIAL FOR
STRONGER STORMS WITH BETTER WIND FIELDS ALOFT HELPING SHEAR
VALUES...AND SOME POTENTIAL INSTABILITY AHEAD OF THESE WAVES. PLENTY
OF TIME TO MONITOR THE TRENDS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 203 PM EDT TUE JUL 28 2015

THERE IS LITTLE QUESTION VFR CONDITIONS WILL PREVAIL AT ALL OF
OUR TAF SITES THROUGH AT LEAST 09Z WEDNESDAY. THE SHOWERS AND
THUNDERSTORMS OVER WISCONSIN...EASTERN IOWAN AND WESTERN ILLINOIS
ARE NOT EXPECTED TO REACH SOUTHWEST LOWER MICHIGAN THANKS TO THE
DEEP INFLOW OF DRY AIR OFF THE CANADIAN SHIELD...BELOW 10000 FT
AGL THIS AFTERNOON. AT MOST EXPECT LAYER MID AND HIGH CLOUDS AS
THE CLOUDS THAT REMAIN FROM THOSE SHOWERS MOVE OVERHEAD LATER THIS
AFTERNOON INTO THIS EVENING.

ANOTHER AREA OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP
WEST OF CHICAGO AFTER MIDNIGHT AND HEAD TOWARD SOUTHWEST LOWER
MICHIGAN JUST AFTER SUNRISE. THIS AREA OF SHOWERS WILL ALSO RUN
INTO DRY AIR IN FRONT OF IT AND HAVE A HARD TIME MOVING ACROSS THE
TAF SITES...HOWEVER THIS TIME THERE IS A FRONT HELPING THE CAUSE
SOME. AS A RESULT I PUT VCSH AT MOST OF THE TAF SITES FOR THE MID
MORNING HOURS. FOR LAN AND JXN...BEING FARTHER EAST... I PUT VCTS
SINCE BY THE TIME THE SHOWERS WOULD GET THAT FAR EAST...THERE MAY
BE ENOUGH INSTABILITY FOR THUNDERSTORMS. IF THERE WOULD BE ANY
MVFR OR IFR... IT WOULD BE WITH THOSE SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
ISSUED AT 330 AM EDT TUE JUL 28 2015

INCREASING SOUTH WINDS AHEAD OF THE COLD FRONT LATE TONIGHT/EARLY
WEDNESDAY WILL BUILD WAVES... BUT PROBABLY ONLY TO 1 TO 3 FEET NORTH
OF HOLLAND. THE WESTERLY FLOW AND SLIGHT COLD ADVECTION BEHIND THE
FRONT LATE WEDNESDAY INTO EARLY THURSDAY COULD LEAD TO A PERIOD OF 2
TO 4 FOOTERS.


&&

.HYDROLOGY...
ISSUED AT 1250 PM EDT TUE JUL 28 2015

RIVER LEVELS ARE FALLING AND WELL BELOW BANKFULL. WITH UNDER A
HALF INCH OF PRECIPITATION EXPECTED INTO NEXT WEEK... THESE
CONDITIONS SHOULD CONTINUE.

&&

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

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...WDM
HYDROLOGY...63
MARINE...MEADE


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