Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 311824
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
224 PM EDT SUN AUG 31 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EDT SUN AUG 31 2014

WV IMAGERY AND RUC ANALYSIS INDICATED A MID LEVEL RIDGE FROM THE
UPPER MS VALLEY THROUGH WRN LAKE SUPERIOR BTWN A DEPARTING SHRTWV
TROUGH INTO NRN LOWER MI AND AN UPSTREAM SHRTWV OVER THE WRN
DAKOTAS. ISOLATED SHOWERS ASSOCIATED WITH THE COMMA HEAD OF THE MI
SHRTWV WERE EXITING THE ERN CWA. HOWEVER...EXTENSIVE LOW LEVEL
MOISTURE/LOW CLOUDS PERSISTED OVER MUCH OF UPPER MI...EXCEPT FROM
CMX/P59 TO IWD. AT THE SFC...A RIDGE EXTENDED FROM JAMES BAY AND NRN
ONTARIO INTO WRN UPPER MI AND NW WI.

TODAY...AS THE 850-700 MB MOISTURE DEPARTS THIS MORNING AND DAYTIME
HEATING/MIXING INCREASES...EXPECT THAT THE REMAINING CLOUDS OVER THE
CNTRL AND EAST WILL THIN OUT AND GIVE WAY TO SCT CU BY AFTERNOON.
WITH SUBSIDENCE LIMITING INVERSION HEIGHTS CLOSER TO 900 MB...MAX
TEMPS MAINLY IN THE MID 70S ARE IN STORE WITH SOME LOWER READINGS
NEAR THE GREAT LAKES WHERE E OR SSE WINDS PREVAIL.

TONIGHT...AS THE DAKOTAS SHORTWAVE AND ASSOCIATED SFC TROUGH
APPROACH THE REGION SRLY FLOW AND MOISTURE ADVECTION WILL INCREASE.
AS PWAT VALUES CLIMB INTO THE 1.5-2.0 INCH RANGE FROM NW WI TO NEAR
IWD AND LARGE SCALE LIFT INCREASES WITH UPPER LEVEL DIV 700-300 MB
QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH...SHRA/TSRA THAT DEVELOP
OVER MN WILL SPREAD TOWARD AND INTO THE CWA...MAINLY AFT 06Z. WITH
THE INITIAL PUSH OF 850-700 MB THETA-E ADVECTION SOME ISOLD SHRA/TSRA
MAY ALSO SPREAD INTO N CNTRL UPPER MI DURING THE EVENING...BUT
CONFIDENCE INTO CNTRL UPPER MI IS LOW WITH ONLY SLIGHT CHANCE POPS
MENTIONED. THE BEST CHANCE FOR SVR STORMS IS EXPECTED TO REMAIN WEST
OF THE CWA...CLOSER TO THE GREATER INSTABILITY. HOWEVER...WITH
MUCAPE VALUES TO AT LEAST 1K J/KG AND FAVORABLE 0-1KM/0-6KM SHEAR
TO 30/40 KNOTS...SOME STRONG STORMS WILL BE POSSIBLE WITH GUSTY
WINDS AND SMALL HAIL. THE MAIN HAZARD WITH TSRA LATE TONIGHT WILL BE
LOCALLY HEAVY RAIN WITH SOME ISOLD 1-2 INCH AMOUNTS POSSIBLE.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 224 PM EDT SUN AUG 31 2014

ASIDE FROM SOME MINOR PRECIP AMOUNTS POSSIBLE EARLY IN THE NIGHT
OVER FAR ERN UPPER MI DUE TO THE MON COLD FRONT EXITING THE
AREA...MON NIGHT AND TUE LOOK DRY FOR THE MOST PART AS SFC RIDGING
MOVES IN. A COUPLE MODELS SHOW A FEW HUNDREDTHS OF AN INCH OF QPF
TUE AFTERNOON AS A SHORTWAVE MOVES THROUGH THE REGION...BUT FORECAST
SOUNDINGS ARE JUST TOO DRY AND THE SHORTWAVE LOOKS TO GO TOO FAR SE
OF THE AREA TO HAVE PRECIP IN THE FORECAST. WILL KEEP A DRY
FORECAST. HIGH TEMPS LOOK TO BE FROM THE UPPER 60S TO MID 70S AS
850MB TEMPS WILL BE 9-11C.

FOR WED...SFC RIDGING MOVES E...SO SLY LOW LEVEL FLOW WILL BE ON THE
INCREASE UNDER ZONAL UPPER FLOW. MODELS SHOW VERY SUBTLE SHORTWAVE
ENERGY MOVING THROUGH THE AREA WED. OF COURSE...THIS FAR OUT THE
CONFIDENCE OF PRECIP RESULTING FROM WEAK SHORTWAVES IS MINIMAL...SO
WILL HAVE SLIGHT CHANCE POPS AT BEST.

FOR WED NIGHT THROUGH FRI NIGHT...MODELS TEND TO GENERALLY AGREE
THAT A STRONGER SHORTWAVE WILL MOVE INTO THE NCENTRAL CONUS AND
EVENTUALLY ACROSS OR NEAR THE CWA LATE FRI INTO FRI NIGHT. WHILE THE
ECMWF HAS SHOWN BETTER RUN TO RUN CONTINUITY WITH THE SHORTWAVE AND
RESULTING SFC LOW...THE UPPER LEVEL ENERGY IS CURRENTLY OVER THE
SEWARD PENINSULA OF ALASKA AND WILL ONLY ENTER THE CONUS OVER WA TUE
NIGHT. SHORTWAVE ENERGY THAT HAS YET TO REALLY DETACH FROM THE
PARENT UPPER LEVEL LOW OVER ALASKA NORMALLY LEADS TO PRETTY LOW
CONFIDENCE IN TIMING/TRACK 4-5 DAYS OUT...WHICH IS THE CASE HERE. DO
HAVE TO PREFER THE ECMWF SINCE IT HAS BEEN MORE STEADY FROM RUN TO
RUN...BUT CONFIDENCE IS STILL LOW SINCE THE GFS IS AROUND 18 HOURS
SLOWER AND FARTHER S WITH THE PASSAGE OF THE RESULTING SFC LOW THAN
THE ECMWF. OVERALL CONFIDENCE IN RAIN SOMEWHERE IN THE THU-FRI TIME
SPAN IS GOOD ENOUGH FOR HIGH CHANCE POPS...BUT TIMING WILL NEED TO
BE REFINED OVER THE NEXT FEW FORECASTS. AT THIS TIME...THE BEST
CHANCES FOR STRONG TO SEVERE STORMS /USING THE PREFERRED TIMING AND
TRACK OF THE ECMWF/ IS WED NIGHT INTO THU MORNING ALONG THE WARM
FRONT WHERE ELEVATED STORMS WOULD BE POSSIBLE...AND AGAIN LATE THU
INTO THU NIGHT AS MLCAPES APPROACH 3000J/KG WITH 0-6KM SHEAR OF
40-50KTS AND 0-1KM SHEAR AROUND 30KTS ALONG AND AHEAD OF THE COLD
FRONT. WHILE ALL MODES OF SEVERE WEATHER WOULD BE POSSIBLE WITH THE
ECMWF SOLUTION LATE THU INTO THU NIGHT...IT IS ALSO THE WORST CASE
SCENARIO. THE FARTHER S GFS WOULD RESULT IN MORE CLOUDS ON FRI
BEFORE THE SFC LOW AND COLD FRONT MOVE THROUGH...SO INSTABILITY
WOULD NOT BE AS STRONG. WILL NEED TO MONITOR AS CONFIDENCE IN SEVERE
CHANCE ARE LIMITED AND MODEL GUIDANCE WILL LIKELY CHANGE. FARTHER N
ECMWF IS ALSO WARMEST WITH 850MB TEMPS RISING TO AROUND 20C THU
AFTERNOON...WHICH WOULD RESULT IN HIGH TEMPS WELL INTO THE 80S OR
EVEN LOW 90S DEPENDING ON CLOUD AND PRECIP COVERAGE. WILL GO WITH A
MORE CONSENSUS APPROACH TO TEMPS GIVEN UNCERTAINTY.

NEXT WEEKEND LOOKS DRY AS COOLER HIGH PRESSURE SETTLES IN BEHIND THE
PREVIOUS SYSTEM. 850MB TEMPS FALL TO 3-4C ON SAT AND WARM TO 6-8C ON
SUN...SO COOLER CONDITIONS WITH HIGHS IN THE 60S TO LOW 70S ARE
EXPECTED.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1206 PM EDT SUN AUG 31 2014

EXPECT LINGERING SC IFR CIGS AT CMX AND SAW TO DISSIPATE WITH MIXING
EARLY THIS AFTERNOON. OTHERWISE...VFR CONDITIONS WILL CONTINUE UNTIL
LATE TONIGHT INTO MON MORNING AS NEXT SYSTEM AND RAIN ARRIVES BY
THEN FOR IWD AND CMX. SAW IS A DIFFERENT STORY AS THERE IS A
POTENTIAL OF AN UPSLOPE LOW CLOUD/FOG EVENT FROM LAKE MICHIGAN WITH
SOUTH WINDS AND PUT THAT SCENARIO OF LIFR/IFR CONDITIONS WITH FOG
AND LOW CLOUDS THERE TONIGHT. ON MON MORNING...RAIN WILL HAVE
STARTED AND IFR/LIFR CONDITIONS FOR ALL SITES WILL PREVAIL. LLJ SETS
UP TONIGHT OFF THE SFC AT ALL SITES AND PUT IN LLWS TO COVER IT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EDT SUN AUG 31 2014

WINDS WILL BE LESS THAN 20 KTS OR LESS THROUGH MOST OF THE PERIOD
EXCEPT FOR A PERIOD OF SE TO S GUSTS OF 20 TO 30 KNOTS TONIGHT AND
MONDAY MORNING. WINDS WILL THEN VEER WRLY TO 20 KNOTS MON AFTERNOON
AND MON NIGHT IN THE WAKE OF A LOW PRESSURE SYSTEM AND COLD FRONT.
WIDESPREAD FOG WILL CONTINUE THROUGH THIS MORNING AND THEN DEVELOP
AGAIN TONIGHT INTO MONDAY NIGHT.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB






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