Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 171934
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
334 PM EDT SUN AUG 17 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALF BTWN
A SLOWLY RETREATING...DEEP UPR TROF IN QUEBEC AND AN UPR RDG IN THE
PLAINS/UPR MS RIVER VALLEY. SFC HI PRES UNDER THIS RDG AXIS IS
LOCATED JUST NNW OF LK SUP. THE LLVL NE FLOW ON THE SRN FLANK OF
THIS HI IS FUNNELING SOME COOL...MOIST AIR INTO THE UPR LKS BLO
SHARP SUBSIDENCE INVRN ARND H85 AS SHOWN ON THE LOCAL 12Z RAOBS. THE
RESULT HAS BEEN A GOOD DEAL OF LO CLD COVER. THERE WAS EVEN SOME
DRIZZLE INTO THE EARLY AFTN OVER THE HIER TERRAIN OF THE NCENTRAL...
WHERE THE NE WIND PRESENTS A SHARPER UPSLOPE COMPONENT. BUT WITH
DAYTIME HEATING UNDER THE MID LVL DRY AIR AND SOME DRY H95-9
ADVECTION FM THE NE...THE LO CLDS ARE SHOWING SIGNS OF BREAKING
UP...ESPECIALLY IN AREAS THAT EXPERIENCE DOWNSLOPE FLOW. LOOKING TO
THE W...A VIGOROUS SHRTWV IN SRN SASKATCHEWAN IS MOVING EWD JUST N
OF THE CNDN BORDER AND TENDING TO SUPPRESS THE UPR RDG IN THE
PLAINS. THERE IS ANOTHER WEAKER SHRTWV AHEAD OF THIS FEATURE MOVING
THRU MN. CLDS ALONG WITH SHOWERS/A FEW TS ASSOCIATED WITH THIS
DISTURBANCE/OVERALL H85 THETA E ADVCTN IN THE LARGER SCALE SW FLOW
AHEAD OF THE STRONGER SASKATCHEWAN SHRTWV ARE APRCHG DULUTH EARLY
THIS AFTN.

MAIN FCST CONCERNS INTO THIS EVNG ARE FOCUSED ON LO CLD TRENDS.
TIMING/COVERAGE OF SHOWERS ASSOCIATED WITH PAIR OF UPSTREAM SHRTWVS
ARE THE CONCERNS FOR LATER TNGT AND MON.

LATE TODAY/TNGT...ALTHOUGH THE COMBINATION OF SOME LLVL DRY ADVCTN
AND DAYTIME HEATING MAY BREAK UP THE LO CLDS NOW IMPACTING THE CWA
THRU THIS AFTN...FAIRLY HI INVRN BASE OBSVD ON THE 12Z RAOBS WL
PROBABLY MAINTAIN BKN LO CLDS AT MANY LOCATIONS NOT IMPACTED BY
DOWNSLOPING FLOW AS THE SLOWLY RISING LCL WL REMAIN UNDER THE HIER
INVRN BASE. BUT THE LATEST TRENDS INDICATE THESE CLDS SHOULD BE
ALMOST COMPLETELY GONE BY 00Z. AFTER THIS EVNG...CLD COVER/SCT
SHOWERS NOW APRCHG DLH ARE LIKELY TO SPREAD INTO THE WRN CWA IN
ADVANCE OF LEAD SHRTWV AND WHERE STRONGER H85 THETA E ADVCTN WL
DVLP. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR E WHERE THERE IS
LIKELY TO BE A LONGER PERIOD OF MOCLR SKIES/LGT WINDS CLOSER TO SFC
HI MOVING FM ERN LK SUP INTO ADJOINING ONTARIO. ADDED SOME PATCHY
FOG TO THE FCST IN THIS AREA WHERE TEMPS ARE EXPECTED TO FALL BLO
THE CROSS OVER DEWPTS OBSVD THIS AFTN.

MON...MAIN SHRTWV NOW MOVING THRU SRN SASKATCHEWAN IS FCST TO MOVE
INTO MN DURING THE AFTN. ALTHOUGH SOME SCT SHOWERS ASSOCIATED WITH
THE LEAD DISTURBANCE/AREA OF H85 THETA E ADVCTN MAY SPREAD INTO THE
CENTRAL AND ERN CWA...THESE ARE MORE LIKELY TO WEAKEN WITH TIME AS
THE CLUSTER MOVES TOWARD THE SHRTWV RDG AXIS/DRIER MID LVL AIR ON
THE WRN FLANK OF THE SLOW MOVING QUEBEC TROF. MORE NMRS SHOWERS ARE
LIKELY TO MOVE INTO THE W HALF OF THE CWA IN THE AFTN UPON THE
ARRIVAL OF DEEPER MSTR/MORE VIGOROUS DYANMIC SUPPORT ASSOCIATED WITH
THE MORE VIGOROUS TRAILING SHRTWV IN THE PRESENCE OF DAYTIME
HEATING. WITH FCST MUCAPES NO HIER THAN 100-200 J/KG ASSOCIATED WITH
A GOOD DEAL OF CLD COVER/EXPECTED DAYTIME HI TEMPS MAINLY IN THE
60S...WL LEAVE OUT A MENTION OF TS EXCEPT OVER THE FAR W...WHERE THE
MORE UNSTABLE GFS HINTS MUCAPES MAY REACH 500 J/KG CLOSER TO THE
INCOMING DISTURBANCE/COLDER AIR ALF.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014

AT 00Z TUESDAY THE NEXT 500MB WAVE WILL BE SET UP ACROSS MN THROUGH
W ONTARIO. MID/LONG TERM MODELS INDICATE THAT THIS FEATURE WILL
DEVELOP INTO A LOW 12-18Z TUESDAY OVER E MN AND THE W HALF OF THE
MQT CWA. AT THAT POINT...LITTLE MOVEMENT WILL BE EXPECTED AT 500MB
UNTIL AFTER DAYBREAK WEDNESDAY...AS THE 500MB SITS AND SPINS ACROSS
UPPER MI AND LAKE SUPERIOR. THE SFC LOW SHOULD TRACK FROM N AND
CENTRAL MN AT 00Z TUESDAY NEAR THE WI/UPPER MI BORDER ON
TUESDAY...BEFORE EXITING ACROSS LAKE MI TUESDAY NIGHT...AND LOWER MI
ON WEDNESDAY. WITH UPPER MI STAYING ON THE N SIDE OF THE SFC LOW
EXPECT A PERIOD OF CLOUDY CONDITIONS...WITH AFTERNOON TEMPS ON
TUESDAY AVERAGING AROUND 5F BELOW THE SEASONAL NORMAL VALUES. THE
BEST CHANCE FOR PRECIP IS DIFFICULT TO PIN DOWN AT THIS POINT...AS
FCST MODELS VARY SIGNIFICANTLY WITH THE SMALLER SCALE FEATURES WITH
THIS DEVELOPING SYSTEM. WILL CONTINUE TO GO RELATIVELY GENERAL WITH
THE POPS AT THIS POINT. WILL KEEP TS POTENTIAL TO A MINIMUM...GIVEN
THE TRACK OF THE SFC LOW MAINLY TO OUR S...AND MU CAPE VALUES OVER
THE FAR W AOB 100J/KG FAR W TUESDAY MORNING. TUESDAY DURING THE DAY
DOESN/T LOOK MUCH MORE IMPRESSIVE...TOPPING OUT ALONG THE WI BORDER
GENERALLY AROUND 200 J/KG OR LESS /RESTRICTED TS MENTION TO CENTRAL
U.P./.

THE 500MB RIDGE WILL BRIEFLY BUILD OVERHEAD LATER WEDNESDAY INTO
EARLY THURSDAY. OUT OF THE WORK WEEK FROM TUESDAY ON...THIS SHOULD
BE THE DRIEST PERIOD. WILL TRY TO SHOW A BIT MORE IN OUR
FCST...DESPITE THE PW VALUES REMAINING 80-140 PERCENT OF NORMAL
/LOWEST E/.

THE CHANCE OF SHOWERS RETURN LATE THURSDAY INTO FRIDAY AS A
SHORTWAVE/TROUGH GLANCES THE AREA. TS MAY RETURN ON FRIDAY. EXPECT
WAA FRIDAY TO PUSH 850MB TEMPS UP TO 15-19C. IF CLOUDS AND PRECIP
CAN STAY TO A MINIMUM...SFC SHOULD SHIFT TO ABOVE NORMAL READINGS.

AS FOR THE OPEN HOUSE AT THE MQT NWS ON SATURDAY 10AM-2PM
EDT...THERE IS ENOUGH DISCREPANCIES AT THIS POINT IN THE FCST MODEL
DATA TO KEEP A GENERAL BLEND OR CONSENSUS GOING. BOTH THE GFS AND
ECMWF SHOW A 500MB LOW TO THE W OF UPPER MI AT 12Z.
HOWEVER...LOCATIONS VARY FROM N MANITOBA TO THE DAKOTAS...WITH A SFC
LOW OR TROUGH EITHER JUST TO OUR W OR OVER W UPPER MI. IF THE 17/00Z
AND 06Z GFS RUNS ARE CORRECT...WINDS NEAR 20KTS WILL BE POSSIBLE.
THE 12Z RUN DID DIMINISH THESE STRONG WINDS...DOWN TO AROUND 10KTS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 123 PM EDT SUN AUG 17 2014

WITH DAYTIME HEATING/DRY AIR SLOWLY ENCROACHING FM THE NE TO THE S
OF HI PRES MOVING INTO NRN LK SUP...EXPECT LO CLDS/MVFR CIGS
IMPACTING THE TAF SITES TO GIVE WAY TO CLRG/VFR CONSITIONS THRU THE
AFTN. MORE CLDS AND EVEN A FEW -SHRA IN ADVANCE OF DISTURBANCE
SPREADING E FM MN WL ARRIVE OVER THE W OVERNGT. PER UPSTREAM OBS IN
MN...FCST MVFR CIGS TO ARRIVE AT IWD AND THEN CMX ON MON MRNG AS
DEEPER MSTR ASSOCIATED WITH AN APRCHG DISTURBANCE OVERSPREADS THESE
SITES. ALTHOUGH THIS DEEPER MSTR IS LIKELY TO REMAIN W OF SAW THRU
THIS TAF PERIOD...SOME FOG MAY DVLP AT THAT SITE OVERNGT. DID NOT
FCST A LOWER CONDITION ATTM WITH EXPECTATION THAT HI CLDS PUSHING E
OF THE APRCHG DISTURBANCE MAY LIMIT DIURNAL COOLING SUFFICIENTLY TO
PREVENT FOG.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 17 2014

EXCEPT FOR A BRIEF PERIOD OVER EASTERN LAKE SUPERIOR LATE MON NIGHT
INTO TUE WHEN WINDS MAY REACH 20-25 KTS UNDER A SHARPER PRES
GRADIENT BETWEEN HI PRES IN QUEBEC AND A LO TRACKING THRU THE UPPER
MIDWEST...EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE
THE CHILLY WATERS OF LAKE SUPERIOR.
&&

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

$$

SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC



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