Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 252025
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
425 PM EDT MON MAY 25 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 424 PM EDT MON MAY 25 2015

WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
MN INTO CO AND A RIDGE OVER THE ERN CONUS RESULTING IN SW FLOW FROM
THE SRN PLAINS TO THE WRN LAKES. A SHORTWAVE TROUGH THAT BROUGHT
WIDESPREAD RAIN ACROSS UPPER MI INTO THE EARLY AFTERNOON WAS LIFTING
NE THROUGH ERN LAKE SUPERIOR LEAVING A PROMINENT DRY SLOT INTO CNTRL
UPPER MI. AT THE SFC...LOW PRES WAS LOCATED OVER W CNTRL UPPER MI
WITH A TROUGH EXTENDING BACK THROUGH CNTRL MN INTO SE SD.
UPSTREAM...ANOTHER WEAKER SHRTWV SUPPORTED SOME TSRA OVER NRN IA.
ENOUGH INSTABILITY HAD DEVELOPED OVER NRN WI FOR SOME ISOLD -SHRA TO
DEVELOP IN THE WAKE OF THE LARGER RAIN AREA.

TONIGHT...MODELS ALONG WITH RADAR/SATELLITE TRENDS SUGGEST THAT THE
NRN IA PCPN MAY SPREAD TOWARD THE S AND E PORTION OF THE CWA BY LATE
THIS EVENING. ALTHOUGH THE MODELS ALSO HINT AT THE POTENTIAL FOR
ADDITIONAL PCPN ASSOCIATED WITH A SHRTWV OVER SE SD THAT COULD MOVE
INTO W UPPER MI...CONFIDENCE IS LOWER. OTHERWISE...MILD CONDITIONS
WITH LOWS IN THE MID50S ARE EXPECTED WITH LIGHT SW WINDS PREVAILING.

TUE...THE SHRTWV OVER NRN TX THAT SUPPORTED A VERY LARGE MCS IS
EXPECTED TO LIFT TOWARD THE WRN LAKES BY LATE TUE BRINGING
INCREASING CHANCES FOR PCPN DURING THE AFTERNOON. THERE IS MORE
UNCERTAINTY ON WHERE THE PCPN WILL DEVELOP AS THE GFS/ECMWF KEEP THE
RAIN FARTHER WEST COMPARED TO THE NAM/REG-GEM. WITH MUCAPE VALUES
INTO THE 500-1000 J/KG RANGE...SOME TSRA WILL BE POSSIBLE.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 304 AM EDT MON MAY 25 2015

SLIGHT CHANCES OF RAIN TUE MORNING WILL GIVE WAY TO INCREASED RAIN
CHANCES IN THE AFTERNOON/EVENING AND INTO TUE NIGHT AS SHORTWAVE
ENERGY MOVES THROUGH THE REGION. STILL THE USUAL MODEL UNCERTAINTY
WITH SHORTWAVE ENERGY THAT WILL BE MODIFIED BY CONVECTION...BUT THE
OVERALL SIGNAL IS GENERALLY AGREED ON. DEPENDING ON DETAILS THAT
WILL HAVE TO BE SORTED OUT LATER...ANYWHERE FROM 300 TO 1000 J/KG OF
CAPE MAY BE REALIZED TUE AFTERNOON/EVENING...SO THUNDER WILL REMAIN
IN THE FORECAST. STRONGER THUNDERSTORMS CAN NOT BE RULED OUT...BUT
GIVEN UNCERTAINTY WILL NOT PLAY THAT UP TOO MUCH YET.

AN UPPER WAVE MOVING THROUGH ON WED WILL INTERACT WITH ANY
INSTABILITY DURING PEAK HEATING. THE QUESTION REMAINS (WITH PLENTY
OF UNCERTAINTY) OF HOW MUCH INSTABILITY WILL RESULT. MODEL RANGE OF
CAPE VALUES IS CURRENTLY BETWEEN A COUPLE HUNDRED J/KG AND WELL OVER
1000 J/KG...SO WILL CERTAINLY NEED TO CONTINUE TO WATCH THE
SITUATION CLOSELY. DO THINK THAT PRECIP POTENTIAL IS LOWER THAN TUE
AS THE FORCING IS WEAKER...BUT THE CONDITIONAL THREAT OF
THUNDERSTORMS STILL EXISTS.

AN UPPER TROUGH AND ASSOCIATED SHORTWAVES WILL BRING PRECIP TO THE
AREA LATE THU EVENING INTO FRI NIGHT USING CONSENSUS TIMING (THE GFS
IS FASTER THAN THE ECMWF). COULD SEE THUNDER AS WELL.

A SFC HIGH DOMINATING NEXT WEEKEND WILL KEEP THE FORECAST DRY AND
COOLER AS 850MB TEMPS DROP TO AROUND 0C. TEMPS LOOK TO BE AS MUCH AS
10 DEGREES BELOW NORMAL OVER THE WEEKEND.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 203 PM EDT MON MAY 25 2015

RAIN WILL CONTINUE TO BRING IFR/LIFR CONDITIONS TO IWD/SAW. THERE
COULD BE SOME IMPROVEMENT BY MID TO LATE AFTERNOON AS WINDS SHIFT TO
THE WSW BEHIND FROPA. IMPROVEMENT IS MORE LIKELY TO OCCUR AT SAW AS
WINDS WILL HAVE A DOWNSLOPE COMPONENT WHERE A PERIOD OF VFR
CONDITIONS IS EXPECTED. MEANWHILE...MOIST EASTERLY UPSLOPE FLOW OFF
OF LAKE SUPERIOR INTO THE KEWEENAW PENINSULA WILL KEEP VLIFR
CONDITIONS AT CMX THAT MAY DROP BLO LANDING MINIMUMS ONCE THE RAIN
DIMINISHES. ONCE THE WINDS BECOME WRLY THIS EVENING...CONTINUED VLIFR
CONDITIONS ARE EXPECTED. IMPROVEMENT TO MVFR IS POSSIBLE TUE MORNING
AS CIGS GRADUALLY LIFT ABOVE 1K FT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 255 AM EDT MON MAY 25 2015

LIGHT WINDS INCREASE TODAY AS A LOW PRESSURE SYSTEM MOVES ACROSS
WESTERN LAKE SUPERIOR.  EAST WINDS MAY REACH 25 KTS...STRONGEST OVER
WESTERN LAKE SUPERIOR AND ALSO NORTHERN LAKE MICHIGAN AND THE BAY OF
GREEN BAY. LOW SLIDES OVERHEAD ON MONDAY NIGHT SO THE WINDS WILL
DIMINISH. WINDS THE REST OF THE FORECAST PERIOD ARE EXPECTED TO STAY
AT OR BELOW 20 KTS. FOG WILL LINGER THROUGH WEDNESDAY MORNING AND
MAY BE DENSE AT TIMES. ONCE IT IS EVIDENT HOW EXPANSIVE THE FOG
IS...A DENSE FOG ADVISORY MAY BE NEEDED.
&&

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

$$

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


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