Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 270743
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
343 AM EDT WED MAY 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM EDT WED MAY 27 2015

A SHORTWAVE AND ASSOCIATED SFC LOW ARE DRIVING RAIN SHOWERS OVER
MAINLY WESTERN AND CENTRAL UPPER MI EARLY THIS MORNING. THIS AXIS OF
GREATEST PRECIP AMOUNTS/COVERAGE WILL SHIFT E OVER PRIMARILY THE ERN
U.P. THIS MORNING AND WILL EXIT E OF THE CWA BY 21Z TODAY.

MEANWHILE...A WEAKER SHORTWAVE CURRENTLY OVER SRN SASKATCHEWAN MOVE
ACROSS WRN AND CENTRAL UPPER MI LATE THIS AFTERNOON INTO THIS
EVENING. THE GREATEST FORECAST UNCERTAINTY IN THE SHORT TERM IS
RELATED TO CONVECTIVE POTENTIAL WITH THIS SECOND SHORTWAVE.
CONVECTIVE POTENTIAL WILL RELY HEAVILY ON HOW FAST PRECIP AND CLOUD
COVER MOVE OUT TODAY...DETERMINING INSTABILITY LEVELS. ALSO IN
QUESTION IS THE EXACT TRACK OF THE SHORTWAVE...WHICH IS SHOWN
HEADING S OF THE CWA BY A COUPLE MODELS. AT THIS POINT...IT APPEARS
THERE WILL BE CONVECTION FIRING ALONG THE LAKE BREEZE BOUNDARIES
OVER NCENTRAL UPPER MI LATE THIS AFTERNOON AND THIS EVENING AND
POSSIBLY ALONG THE WI BORDER AS WELL. AS FOR STRENGTH OF THE
CONVECTION...CONFIDENCE IS QUITE LOW. MODELS RANGE FROM A FEW
HUNDRED J/KG OF CAPE TO 1500 J/KG. ALSO...MODELS INDICATE THAT
EFFECTIVE SHEAR WILL INCREASE FROM VERY MARGINAL LEVELS EARLY TODAY
TO 30-35KTS AROUND EXPECTED TIME OF CONVECTIVE INITIATION (21Z) AS
THE SHORTWAVE MOVES INTO THE AREA. ADDITIONALLY...WNW FLOW IS THE
FAVORED FLOW FOR STRONGER CONVECTION OVER THE NCENTRAL. CERTAINLY A
CONDITIONAL AND VERY UNCERTAIN STRONG/SEVERE THREAT. WILL NOT HYPE
THE THREAT UP MUCH RIGHT NOW...ESPECIALLY GIVEN THAT IT WILL BE
FAIRLY LATE IN THE DAY...MORE INTO THE EVENING TIME FRAME...SO THE
DAY SHIFT WILL HAVE PLENTY OF TIME TO MONITOR TRENDS AND MAKE
REFINEMENTS. OTHERWISE...EXPECT HIGH TEMPS TODAY IN THE 60S E HALF
TO 70S W HALF...LOCALLY COOLER NEAR LAKE SUPERIOR.

REMAINING CONVECTION (IF ANY) WILL DISSIPATE TONIGHT AS THE
SHORTWAVE MOVES OUT AND INSTABILITY DIMINISHES. SKIES WILL BE
CLEARING INITIALLY...BUT CLOUDS WILL DEVELOP NEAR LAKE SUPERIOR AS
FLOW BECOMES NELY LATER IN THE NIGHT. LOWS WILL MAINLY BE IN THE
40S...WITH LOWS AROUND 50 OVER THE SCENTRAL.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 411 PM EDT TUE MAY 26 2015

WEDNESDAY NIGHT...THE FRONT WILL BE WELL PAST THE CWA BY WEDNESDAY
EVENING. THE UPPER LEVEL 500MB TROUGH AXIS WILL CONTINUE TO SHIFT TO
THE EAST OF THE U.P. AT THE SAME TIME...THE DEEPER MOISTURE AND
BETTER FORCING WILL SLIDE OUT OF THE AREA ALLOWING ANY LINGERING
SHOWERS OVER THE EAST HALF TO DIMINISH IN THE EVENING HOURS. THIS
BRIEF BREAK WILL BE FAIRLY SHORT LIVED WITH THE NEXT AREA OF LOW
PRESSURE SLIDING INTO THE NORTHERN PLAINS.

THURSDAY THROUGH FRIDAY NIGHT...DURING THE DAY THURSDAY...MUCH OF
THE AREA WILL SEE A CONTINUED BREAK FROM THE RAIN SHOWERS AS THE CWA
WILL CONTINUE TO BE BETWEEN SYSTEMS DURING THAT TIME...WITH THE COLD
FRONT TO THE EAST AND A LOW PRESSURE SYSTEM AND ASSOCIATED COLD
FRONT SLIDING INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA.
MODELS ARE COMING INTO BETTER AGREEMENT WITH LOW PLACEMENT ALONG
WITH COLD FRONT TIMING THURSDAY NIGHT INTO FRIDAY...WITH THE COLD
FRONT MOVING THROUGH DURING PEAK HEATING. THE GFS IS STILL A BIT
MORE PROGRESSIVE WITH THE SYSTEM WHILE THE EC IS A LITTLE SLOWER AT
MOVING THE SYSTEM THROUGH. LATE THURSDAY NIGHT THROUGH FRIDAY
AFTERNOON/EVENING LOOKS TO BE WET WITH SHOWERS AND THUNDERSTORMS
PUSHING INTO THE UPPER GREAT LAKES REGION. ALOFT...A 500 MB TROUGH
WILL PUSH ACROSS THE AREA AROUND THE SAME TIME FRAME...WHILE
LINGERING INTO THE OVERNIGHT HOURS FRIDAY NIGHT AS A RIDGE BEGINS TO
BUILD OVER THE WESTERN CONUS. AS THE FRONT IS EXPECTED TO MOVE IN
DURING PEAK HEATING...MUCAPE VALUES RANGE FROM 500-700 J/KG FROM THE
GFS TO AROUND 800-1100 J/KG FROM THE EC...MAINLY OVER THE INLAND
WEST. OVERALL INSTABILITY WILL BE LARGELY DEPENDENT UPON CLOUD COVER
OR BREAKS IN THE CLOUD COVER AHEAD OF THE SYSTEM. IF SKIES ARE
OVERCAST THROUGH THE DAY THE INSTABILITY WILL BE LOWER...HELPING TO
REDUCE THE SEVERE RISK. SHEAR VALUES ARE PROGGED TO BE AROUND 35 TO
40 KNOTS PERPENDICULAR TO THE FRONT. THE RISK AGAIN WILL BE
CONDITIONAL...DEPENDING LARGELY ON THE PRE-FRONTAL CLOUD COVER. THE
WARMER TEMPERATURES SLIDING ACROSS THE COLD WATERS OF THE GREAT
LAKES WILL ALSO ALLOW WIDESPREAD FOG TO FORM THURSDAY NIGHT INTO
FRIDAY...ESPECIALLY WHEN THE RAIN SHOWERS PUSH OVER THE LAKES.
TRAPPING MOISTURE UNDER A FAIRLY STRONG TEMPERATURE INVERSION AS
NOTED ON BUFKIT SOUNDINGS.

SATURDAY THROUGH THE REMAINING EXTENDED...NICE WEEKEND EXPECTED AS
DRY COOL CANADIAN HIGH PRESSURE IS EXPECTED TO SLIDE ACROSS THE
UPPER GREAT LAKES REGION IN THE WAKE OF THE LOW AND COLD FRONT.
THERE MAY BE A FEW SHOWERS LINGERING SHOWERS OVER THE FAR EAST
SATURDAY MORNING...BUT SHOULD END QUICKLY BY LATE MORNING OR EARLY
AFTERNOON. THE UPPER LEVEL 500MB TROUGH AXIS WILL SHIFT TO THE EAST
OF THE AREA BY SATURDAY EVENING AND OUT OF THE AREA BY SUNDAY. CALM
WINDS ASSOCIATED WITH THE SURFACE HIGH ALONG WITH VERY DRY AIR IN
PLACE WILL ALLOW TEMPERATURES TO DROP BELOW NORMAL...INTO THE 30S
FOR OVERNIGHT LOW TEMPERATURES AND HIGHS IN THE MID 50S TO LOW 60S.
FROST WILL LIKELY DEVELOP SATURDAY NIGHT INTO SUNDAY MORNING ACROSS
INLAND AREAS. THE NEXT AREA OF LOW PRESSURE IS PROGGED TO DEVELOP
OVER THE NORTHERN PLAINS MONDAY NIGHT AND SLOWLY SHIFT EASTWARD INTO
THE UPPER GREAT LAKES LATE TUESDAY. THERE ARE CONSIDERABLE
DIFFERENCES WITH TIMING AND PLACEMENT OF THIS SYSTEM SO CONFIDENCE
IN RAIN CHANCES IS LOW. CONSENSUS OF THE MODELS BROUGHT LIKELY POPS
IN BUT DECIDED TO ADJUST THEM BACK TO CHANCE POPS WITH THE
AFOREMENTIONED ISSUES IN MIND.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 130 AM EDT WED MAY 27 2015

LOW PRES OVER NE WI WILL LIFT NNE ACROSS CNTRL UPPER MI OVERNIGHT...
BRINGING OCNL SHRA TO THE AREA. ABUNDANT LOW-LEVEL MOISTURE/SHRA AND
SOME UPSLOPE FLOW OFF LAKE SUPERIOR WILL ENSURE LIFR CONDITIONS
PREVAIL AT KIWD/KSAW THROUGH THE NIGHT. KCMX WILL DROP TO LIFR
CONDITIONS OVER THE NEXT FEW HOURS AS WINDS BECOME NWLY...WHICH IS
MORE FAVORABLE FOR LOW CONDITIONS. WILL LIKELY SEE SOME PERIODS OF
VLIFR AS WELL DURING BREAKS IN THE PCPN. EXPECT FAIRLY RAPID
IMPROVEMENT FROM W TO E THIS MORNING/EARLY AFTN AS THE LOW PRES
SYSTEM AND ASSOCIATED -SHRA EXIT. ANOTHER DISTURBANCE...THIS TIME
MOVING ESE ACROSS THE AREA...WILL PROBABLY SPARK SCT -SHRA AND ISOLD
TSRA THIS AFTN/EARLY EVENING. LOW CONFIDENCE ON WHERE THE CONVECTION
WILL OCCUR...BUT RIGHT NOW...IT APPEARS KIWD/KSAW HAVE A SOMEWHAT
BETTER POTENTIAL OF SEEING SOME PCPN IN THE AREA THAN KCMX DUE TO
GREATER INSTABILITY BUILD UP IN THE INTERIOR OF UPPER MI. ONLY
INCLUDED A VCSH MENTION FOR NOW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 AM EDT WED MAY 27 2015

WINDS ARE EXPECTED TO STAY AT OR BELOW 20 KNOTS FOR MOST OF THIS
FORECAST PERIOD WITH THE EXCEPTION OF FRI NIGHT INTO EARLY SATURDAY
WHERE THEY WILL BE UP TO 25 KNOTS ACROSS EASTERN LAKE SUPERIOR. FOG
WILL LINGER THROUGH INTO TONIGHT AND WILL BE DENSE AT TIMES.
ADDITIONAL FOG IS EXPECTED TO DEVELOP THURSDAY NIGHT AND FRIDAY
AHEAD OF THE NEXT LOW AND ASSOCIATED COLD FRONT.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...KEC
AVIATION...ROLFSON/TITUS
MARINE...TITUS



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