Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 281800
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
200 PM EDT TUE JUL 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 606 AM EDT TUE JUL 28 2015

WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
THE NRN ROCKIES AND HIGH PLAINS AND A RIDGE FROM THE SRN PLAINS
THROUGH THE GREAT LAKES REGION INTO NRN ONTARIO. WITHIN BASE OF MID-
LEVEL TROUGH A STRONG SHORTWAVE AND DEVELOPING CLOSED LOW WAS
LIFTING NE FROM ERN MONTANA INTO THE WRN DAKOTAS. INSTABILITY
(MUCAPES 1000-2000 J/KG) AND LIFT AHEAD OF SHORTWAVE AND ALONG ASSOC
FRONTAL BOUNDARY HAS SUPPORTED A LARGE MCS OVER THE ERN DAKOTAS AND
WRN MN EARLY THIS MORNING. BY COMPARISION...HIGH PRESSURE OVER THE
GREAT LAKES REGION HAS RESULTED IN GENERALLY CLOUD FREE AND QUIET
CONDITIONS OVER UPPER MI...ALTHOUGH NIGHTTIME TEMPS HAVE BEEN QUITE
WARM... GENERALLY IN THE 60S.

MODELS INDICATE CLOUDS AND POSSIBLY A FEW SHRA FROM DIMINISHING
CONVECTION WITH MCS TO WEST COULD SPREAD INTO WRN UPPER MI THIS
AFTERNOON. DESPITE POSSIBLE INCREASE IN CLOUDS...EXPECT ENOUGH
SUNSHINE BY AFTERNOON TO PUSH TEMPS INTO THE UPPER 80S AND LOWER 90S
AS MOST LOCATIONS AGAIN TODAY. WITH DAYTIME MIXING EXPECT DEWPOINTS
TO LOWER INTO MID TO UPPER 50S AT MOST LOCATIONS WITH EVEN A FEW
LOWER 50S DEWPOINTS POSSIBLE OVER EASTERN SITES. COMBINATION OF HIGH
TEMPS AND LOWERING OF DEWPOINTS WILL RESULT IN INLAND MIN RH/S
DROPPING INTO THE 30S OVER MUCH OF CENTRAL UPPER MI WITH EVEN SOME
MID TO UPPER 20S RH/S OVER THE ERN THIRD OF UPPER MI. THIS WILL
INCREASE FIRE WEATHER CONCERNS TODAY INTO THIS EVENING GIVEN RECENT
STRETCH OF DRY WEATHER. FORTUNATELY SOUTHERLY WINDS AHEAD OF FRONT
SHOULDN/T INCREASE TOO MUCH THROUGH THIS EVENING (GENERALLY LESS
THAN 20 MPH FOR GUSTS). WEST WINDS HOWEVER COULD GET GUSTY IN WAKE
OF FRONT ON WEDNESDAY.

FOCUSING ON PCPN CHCS THIS AFTERNOON INTO TONIGHT AS FRONTAL SYSTEM
FROM PLAINS WORKS ITS WAY ACROSS THE REGION TONIGHT INTO EARLY
WEDNESDAY. MODELS SHOW SOME DIFFERENCES IN FRONTAL TIMING WITH THE
REGIONAL GEM PERHAPS A BIT QUICKER WITH FRONT INITIALLY THAN
NAM...GFS OR ECMWF MODELS. DESPITE MINOR DIFFERENCES MODELS
GENERALLY SHOW COLD FRONT REACHING INTO WRN UPPER MI THIS
EVENING...INTO CENTRAL UPPER MI AROUND 12Z WED AND EXITING ERN UPPER
MI AROUND 18Z WED. MODELS CONSISTENT WITH IDEA THAT BEST DYNAMICS
(MID-LVL Q-VECT CONV) ASSOC WITH FRONTAL SYSTEM WILL BE LIFTING WEST
AND NORTH OF THE UPPER GREAT LAKES TONIGHT...TIED TO MOVEMENT OF
SHORTWAVE AND ASSOC MID-LVL CLOSED LOW WHICH LIFT NE INTO SRN
MANITOBA AND NW ONTARIO TONIGHT. AT SAME TIME...MODELS AND SREF
ENSEMBLE FIELDS INDICATE BEST MOISTURE/INSTABILITY STAYING SOUTH OF
UPPER MI INTO WI BY TIME FRONT MOVES THROUGH TONIGHT WITH MUCAPES
500 TO MAYBE 1000 J/KG FAR WEST IN THE EVENING DECREASING TO ONLY A
FEW HUNDRED J/KG EAST OVERNIGHT. COMBINATION OF BEST DYNAMICS MOVING
WELL TO NORTH AND BEST MOISTURE STAYING SOUTH HAS LED MOST OF
MODELS TO DEPICT MORE A SCATTERED TO BROKEN LINE OF CONVECTION
DEVELOPING ALONG FRONT AS IT MOVES THROUGH UPPER MI TONIGHT. GIVEN
THE UNCERTAINTY WITH DEVELOPING CONVECTION ALONG FRONT HAVE
GENERALLY KEPT ONLY HIGH CHC POPS AND LIMITED LIKELY POPS IN FCST
FOR SCT SHRA/TSRA LATE THIS AFTERNOON/EARLY EVENING WEST SPREADING
ACROSS REST OF FCST TONIGHT.

ALSO DOWNPLAYED THREAT OF SEVERE STORMS IN HWO GIVEN LATER TIMING OF
FRONT TOWARD LATE EVENING OVERNIGHT AS INSTABILITY WILL BE WANING.
ALSO BEST DEEP SHEAR LOOKS TO LAG BEHIND THE FRONT AND OUT OF SYNC
WITH BETTER INSTABILITY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 348 AM EDT TUE JUL 28 2015

A 991MB SURFACE LOW WILL BE LIFTING NORTHEAST ALONG THE
MANITOBA/ONTARIO BORDER AT 12Z WEDNESDAY...WITH A COLD FRONT
STRETCHING SOUTH-SOUTHEAST ACROSS CENTRAL LAKE SUPERIOR AND THROUGH
CENTRAL UPPER MICHIGAN AND SOUTH THROUGH EASTERN WISCONSIN. EXPECT
A BROKEN LINE OF SHOWERS AND THUNDERSTORMS TO BE ONGOING ALONG AND
TO THE EAST OF THE COLD FRONT. WITH INSTABILITY DECREASING THROUGH
THE NIGHT...DON/T EXPECT ANY REALLY STRONG STORMS...ALTHOUGH BRIEF
PERIODS OF HEAVY RAIN IS EXPECTED. THESE SHOWERS/THUNDERSTORMS WILL
CONTINUE TO THE EAST-NORTHEAST THROUGH THE MORNING AND SHOULD LEAVE
THE CWA BY EARLY AFTERNOON (ALONG WITH THE COLD FRONT). THAT COLD
FRONT WILL BRING TEMPERATURE/HUMIDITY RELIEF TO THE REGION ON
WEDNESDAY...AS MUCH DRIER LOW LEVEL AIR MOVES OVER THE REGION AND
HIGHS ONLY RISE INTO THE UPPER 70S WEST AND LOWER 80S EAST. AFTER
CLEARING INITIALLY BEHIND THE FRONT...EXPECT SCATTERED CLOUDS TO
MOVE EAST BACK INTO THE AREA FROM LATE MORNING OVER THE WEST TO THE
AFTERNOON OVER THE CENTRAL...TIED TO 850-700MB MOISTURE ASSOCIATED
WITH THE SOUTHERN EDGE OF THE UPPER TROUGH SWEEPING EAST THROUGH THE
AREA. THE MAIN HAZARD FOR WEDNESDAY WILL BE THE GUSTY WEST-SOUTHWEST
WINDS...ESPECIALLY OVER THE NORTHWEST HALF OF UPPER MICHIGAN AND
LAKE SUPERIOR. MODELS STILL SHOWING A CORE OF 30-45KT 950-900MB
WINDS MOVING OVER THE AREA ON WEDNESDAY AND ASSOCIATED WITH THE
TIGHT PRESSURE GRADIENT BEHIND THE DEPARTING LOW (TIGHTEST FROM THE
KEWEENAW PENINSULA AND NORTH). WITH THE WESTERN LAKE WARMING
UP...DON/T THINK THE MARINE LAYER WILL HAVE AS MUCH OF AN AFFECT AS
EARLIER IN THE YEAR AND FEEL PRETTY COMFORTABLE IN HAVING GUSTS TO
35-40KTS OVER LSZ263-264. THUS...WILL ISSUE A GALE WATCH FOR
WEDNESDAY FOR THE WESTERN HALF OF THE LAKE. OVER THE LAND...STILL
EXPECT THE HIGHEST GUSTS TO OCCUR OVER THE KEWEENAW PENINSULA...WITH
AFTERNOON GUSTS OF 30-40MPH AND MAYBE A FEW GUSTS UP TO 45MPH AROUND
THE BROCKWAY MOUNTAIN AREA. A SECONDARY TROUGH WILL SWEEP ACROSS THE
AREA ON WEDNESDAY EVENING...SWITCHING WINDS TO THE WEST-NORTHWEST
BUT HAVING LITTLE EFFECT ON THE LOW LEVEL WINDS. THIS WILL LIKELY
KEEP SUSTAINED WINDS UP THROUGH MUCH OF THE NIGHT AND POSSIBLY KEEP
GALES GOING OVER THE NORTHERN LAKE INTO THURSDAY MORNING. WITH
LIMITED MOISTURE ASSOCIATED WITH THE FRONTAL PASSAGE...DON/T EXPECT
ANYTHING MORE THAN A FEW TO SCATTERED CLOUDS MOVING THROUGH THE AREA
ON WEDNESDAY NIGHT.

THAT WILL BE THE STORY FOR THE NEXT SEVERAL WAVES DROPPING
SOUTHEAST ACROSS THE AREA UNDER NORTHWEST FLOW ALOFT (OCCURRING
ABOUT EVERY 8-12HOURS INTO THE WEEKEND). THESE SERIES OF WAVES WILL
OCCUR ON THE SOUTH SIDE OF A THE SURFACE AND UPPER LOW MOVING
NORTHEAST ACROSS SOUTHERN HUDSON BAY. MOST WILL BE MOISTURE STARVED
AND WILL LARGELY SHOW PASSING CLOUDS WITH THEM...AND JUST SOME
SLIGHT CHANCES FOR THE THURSDAY NIGHT INTO FRIDAY PERIOD OVER THE
NORTHEAST. WINDS WILL STILL BE GUSTY ON THURSDAY...BUT GRADUALLY
DIMINISH HEADING INTO SATURDAY AS A HIGH PRESSURE RIDGE MOVES OVER
THE AREA. TEMPERATURES WILL BE NEAR NORMAL DURING THIS PERIOD AND
IN THE UPPER 70S TO LOWER 80S. MODELS STILL INDICATING THE BEST
CHANCE FOR PRECIPITATION TO OCCUR WITH ANOTHER SHORTWAVE AND
STRONGER FRONT ON SATURDAY NIGHT INTO SUNDAY MORNING. WILL CONTINUE
TO MENTION CHANCE POPS DURING THAT PERIOD.

MODELS DIVERGE HEADING INTO NEXT WEEK ON THE TIMING OF THE UPPER
LOW SPINNING OVER HUDSON BAY DROPPING SOUTH TOWARDS THE GREAT LAKES
REGION. WHEN THIS OCCURS...IT WILL MARK A SHIFT TO BELOW NORMAL
TEMPERATURES THAT HAS BEEN SHOWN RECENTLY ON THE CFS AND LONG RANGE
ECMWF ENSEMBLES.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 159 PM EDT TUE JUL 28 2015

HIGH CLOUDS WILL BEGIN TO LOWER THIS EVENING RIGHT AHEAD AND ALONG A
COLD FRONT CROSSING W TO E OVER THE AREA. WHILE THUNDERSTORMS WILL
BE POSSIBLE...THE TIMING AND OVERALL COVERAGE IS TOO SMALL TO
INCLUDE IN THE TAF RIGHT NOW. LLWS IS A CONCERN THIS EVENING INTO
THE EARLY MORNING HOURS WEDNESDAY AS WINDS JUST ABOVE THE SFC
CONTINUE AROUND 35KTS. EXPECT THE GUSTY WINDS TO MIX BETTER DURING
THE DAY...LIMITING THE NEED FOR LLWS. EXPECT SIGNIFICANT CLEARING
AND MIXING DIRECTLY BEHIND THE FRONT...WITH SOME SCT-BKN VFR CLOUDS
ENCROACHING BY MID AFTERNOON.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 159 PM EDT TUE JUL 28 2015

FOLLOWING THE PASSAGE OF A COLD FRONT LATE TONIGHT AND WED
MORNING...THE SHARPENING PRES GRADIENT OVER THE UPPER LAKES BETWEEN
HI PRES BUILDING INTO THE CENTRAL PLAINS AND LO PRES MOVING TOWARD
HUDSON BAY WILL SUPPORT WSW GALES UP TO 35 KTS THRU THE DAY ON WED
OVER THE W HALF OF THE LAKE...WHERE THE LAKE GEOGRAPHY TYPICALLY
ENHANCES THIS FLOW. MAINTAINED GOING GALE WATCH FOR THIS AREA.
ALTHOUGH THE GALES ARE EXPECTED TO DIMINISH ON WED EVENING... WINDS
UP TO 25-30 KTS WILL PERSIST THRU THU AS THE PRES GRADIENT SLOWLY
SLACKENS. LIGHTER WINDS UNDER 20 KTS WILL THEN BE THE RULE ON FRI
THRU THE WEEKEND AS A WEAKER PRES GRADIENT MORE TYPICAL OF SUMMER
DOMINATES THAT PERIOD.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR
     LSZ162-240>247-263-264.

LAKE MICHIGAN...
NONE.
&&

$$

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


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