Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 311918
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
318 PM EDT FRI JUL 31 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 452 AM EDT FRI JUL 31 2015

LIKE YESTERDAY...A COUPLE SHORTWAVE DROPPING SOUTHEAST ACROSS THE
AREA WILL BE THE MAIN FEATURES CONTROLLING THE WEATHER FOR THE AREA
TODAY. THE FIRST SHORTWAVE IS CURRENTLY DROPPING SOUTHEAST ACROSS
LAKE SUPERIOR AND WESTERN UPPER MICHIGAN. AT THE SURFACE...THERE IS
A WEAK TROUGH OF 1009MB AT OVER CENTRAL LAKE SUPERIOR. THERE WERE
SHOWERS EARLIER IN THE NIGHT...BUT MOST HAVE SINCE DIMINISHED AND
THERE ARE ONLY A FEW SHOWERS NORTHEAST AND SOUTHWEST OF THE KEWEENAW
AT 430AM. THESE WEAK SHOWERS SHOULD CONTINUE EAST WITH LIMITED
PRECIPITATION POTENTIAL. AS THE SHORTWAVE AND TROUGH CONTINUE EAST
THIS MORNING..COULD SEE SOME REDEVELOPMENT OVER THE FAR EASTERN CWA
AS DIURNAL HEATING DEVELOPS. BUT LATEST TRENDS IN THE MODELS ARE
STARTING TO BACK AWAY FROM THAT IDEA...LARGELY DUE TO THE FASTER
ARRIVAL OF THE SHORTWAVE AND SURFACE TROUGH...WHICH WILL LIKELY PUSH
IT THROUGH TOO EARLY FOR MUCH OF THE EASTERN CWA. WILL CONTINUE TO
MONITOR OVER THE NEXT COUPLE OF HOURS...BUT MAY NEED TO TREND DOWN
THE CHANCE POPS IN PLACE IN THAT AREA. SHIFTING THE FOCUS TOWARDS
THE CENTRAL CWA...DO THINK THAT ISOLATED TO MAYBE EVEN SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THE NORTH CENTRAL U.P. AND
LARGELY WITH DIURNAL HEATING AND ALONG A WEAK CONVERGENCE ZONE DUE
TO VEERING WINDS FROM A SUBTLE LAKE BREEZE (EASTERN MARQUETTE INTO
WESTERN ALGER AND NORTHERN DELTA COUNTIES). BEST INSTABILITY IS TO
THE EAST OF THE AREA IN CHIPPEWA/MACKINAC COUNTIES (ML CAPE OF
NEARING 1000 J/KG)...BUT STILL SHOULD SEE VALUES AROUND 500-750 OVER
THE EASTERN CWA. LIKE YESTERDAY...AN INVERTED-V LOOK TO THE SOUNDING
(DCAPES AHEAD OF MODEL CONVECTION SHOWS VALUES APPROACHING 800-1000
J/KG) WILL LEAD TO THE POTENTIAL FOR BRIEF GUSTY WINDS WITH ANY OF
THE STRONGER THUNDERSTORMS.

THE SECOND SHORTWAVE IS CURRENTLY NEAR LAKE WINNIPEG AND WILL FOLLOW
A SIMILAR AND MAYBE SLIGHTLY FARTHER TO THE SOUTHWEST TRACK AS THE
ONE THIS MORNING. THIS WAVE WILL BE REACHING THE WESTERN U.P. AROUND
MID-LATE AFTERNOON AND WILL TAKE ADVANTAGE OF PEAK HEATING TO LEAD
TO THE POSSIBILITY OF SHOWERS OVER THE INTERIOR WEST LATE THIS
AFTERNOON. OVERALL...THINK MOST OF THE SHOWERS WILL ARRIVE FROM THE
NORTHWEST...SHIFTING SOUTHEAST INTO THE AREA FROM THE TIP OF THE MN
ARROWHEAD AND AND NORTHWEST ONTARIO. HIGH RESOLUTIONS MODELS MATCHED
THAT IDEA...ALONG WITH NCAR ENSEMBLE WRF NEIGHBORHOOD
PROBABILITIES...SO HAVE SPREAD SLIGHT/CHANCE POPS SOUTHEAST FROM
THAT AREA LATE IN THE AFTERNOON AND INTO THE EVENING BEFORE SLOWLY
DIMINISHING OVERNIGHT.

OUTSIDE OF THE SHORTWAVES...WILL CONTINUE TO SEE SOME GUSTY WINDS
OUT THERE TODAY...BUT EXPECT THEM TO BE A LITTLE LOWER THAN THE LAST
2 DAYS DUE TO SLIGHTLY LOWER WITH THE MIXED LAYER WINDS. THAT BEING
SAID...WITH MEAN MOMENTUM TRANSFER VALUES INDICATING GUSTS IN THE
LOW 20KT RANGE THIS AFTERNOON...HAVE FOLLOWED SUIT WITH THE GUST
FORECAST. HAVE THE HIGHEST GUSTS OVER THE KEWEENAW DUE TO THE MORE
EXPOSED LOCATIONS AND BEING WITHIN A POCKET OF STRONGER 925MB WINDS.
THINK THERE WILL BE MORE WIDESPREAD DIURNAL CU TODAY AND HAVE PUSHED
SOME AREAS OVER THE CENTRAL INTO THE MOSTLY CLOUDY CATEGORY.
THIS...COMBINED WITH LOW LEVEL TEMPS BEING A TOUCH COOLER THAN
YESTERDAY...WILL PRODUCE HIGHS A TOUCH COOLER THAN YESTERDAY. WILL
NEED TO KEEP AN EYE ON FIRE WEATHER CONDITIONS AGAIN TODAY...AS THE
DRY LOW LEVEL AIR SHOULD LEAD TO RH VALUES MIXING OUT INTO THE 30S
FOR AREAS OUTSIDE OF THE RAIN SHOWERS. WITH THE CONTINUED WINDY AND
DRY CONDITIONS...WILDFIRE POTENTIAL WILL REMAIN HEIGHTENED.

FINALLY FOR TONIGHT...THERE ARE HINTS AT ANOTHER SHORTWAVE DROPPING
SOUTHEAST ACROSS THE AREA OVERNIGHT TONIGHT. MODELS ARE VARYING ON
THE INTENSITY AND LOCATION OF THE WAVE AND WITH LITTLE NOTICEABLE
FEATURE UPSTREAM...WON/T GO TOO HIGH ON POPS BUT WILL FOLLOW A
SIMILAR SITUATION AS THIS PAST NIGHT WITH SLIGHT CHANCE POPS OVER
NORTHERN LAKE SUPERIOR AND DIMINISHING THROUGH THE NIGHT AS THEY
SLIDE SOUTHEAST.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 314 PM EDT FRI JUL 31 2015

SERIES OF SHRTWVS EMBEDDED IN NW FLOW ALOFT ON THE SRN FLANK OF
CLOSED LO OVER HUDSON BAY WL PASS THRU THE UPR LKS AND BRING THE
THREAT OF SHOWERS/SOME TS TO UPR MI SAT NGT AND SUN. THE LAST SHRTWV
IS FCST TO AMPLIFY THE UPR TROF INTO THE GREAT LKS NEXT WEEK. SO
AFTER NEAR NORMAL TEMPS THIS WEEKEND...NEXT WEEK WL FEATURE MUCH
COOLER WX.

SAT NGT THRU SUN...DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF INITIAL
SHRTWV APRCHG FM THE NW ARE FCST TO MOVE INTO THE UPR LKS ON SAT
EVNG. AS THE LLVL FLOW BACKS MORE TO THE WSW...THE GUIDANCE...
ESPECIALLY THE 12Z NAM...HINTS AT A RETURN OF HIER H85 DEWPTS UNDER
THE INCOMING DYNAMICS. SO DESPITE LOSS OF DAYTIME HEATING...PLAN TO
ADD CHC POPS FOR SAT NGT. BASED ON EXPECTATION OF MORE MSTR RETURN/
CLD COVER...RAISED FCST MIN TEMPS A COUPLE OF DEGREES. CONCERNS THEN
SHIFT TO IMPACT OF DRYING IN THE WAKE OF THE INITIAL SHRTWV ON THE
STRONGER TRAILING DISTURBANCE THAT WL ARRIVE DURING THE DAY ON SUN.
THE 12Z NAM REMAINS THE MOST AGGRESSIVE SHOWING SOME LLVL DRYING/
NEGATIVE H85 THETA E ADVECTION FOLLOWING THE INITIAL DISTURBANCE AND
FCSTS ONLY LIGHT PCPN OVER MAINLY THE SE HALF OF THE CWA WHERE
ARRIVAL OF ATTENDANT COLD FNT WL BE IN BETTER SYNC WITH DAYTIME
HEATING/DESTABILIZATION. BUT EVEN THE DRIER NAM SHOWS MUCAPE INCRSG
TO 500-1000 J/KG...SO WL RETAIN CHC POPS IN THE FCST FOR SUN. FCST
WL SHOW THE HIER POPS FOCUSED OVER THE SE CWA DUE TO GREATER
DESTABILIZATION AND POTENTIAL FOR SOME ENHANCED LLVL CNVGC BTWN COLD
FNT/LK BREEZES OFF LK MI. EXPECT POPS TO DIMINISH NW-SE LATER IN THE
DAY WITH ARRIVAL OF DEEP LYR QVECTOR DVGC AND DRYING FOLLOWING THE
COLD FROPA.

SUN NGT...ARRIVAL OF DNVA/LARGER SCALE QVECTOR DVGC AND SUBSIDENCE
BEHIND THE SHRTWV IN THE PRESENCE OF NOCTURNAL COOLING WL RESULT IN
A DRY FCST. AS THE UPR TROF DEEPENS INTO THE UPR LKS AND H85 TEMPS
FALL TOWARD 6-8C BY 12Z MON...MODELS SHOW SOME INCRSG SFC-H85 MSTR
IN MORE CYC LLVL NW FLOW. EXPECT INCRSG SC OVER MAINLY THE HIER
TERRAIN OF THE NW CWA WITH UPSLOPE WIND COMPONENT AS THE COOLER
PUSHES INTO THE CWA.

MON...WITH WEAKLY CYC NW H85 FLOW...FAIRLY SUBSTANTIAL LLVL MSTR
FCST UNDER LARGER SCALE SUBSIDENCE/MID LVL INVRN AND INCOMING H85
THERMAL TROF...EXPECT AN EXPANSION OF CU/SC WITH DAYTIME HEATING. A
NUMBER OF THE MODELS GENERATE SOME LGT QPF...SO WL RETAIN SOME LO
CHC POPS MAINLY AWAY FM LK SUP TO ACCOUNT FOR THE POTENTIAL OF SOME
RELATIVELY SHALLOW CONVECTION/SHOWERS. WITH H85 TEMPS IN THE 6-8C
RANGE AND A GOOD DEAL OF CLD COVER...EXPECT A MUCH COOLER DAY/BLO
NORMAL TEMPS.

MON NGT...ARRIVAL OF MORE ACYC FLOW/NOCTURNAL COOLING UNDER
CONTINUED LARGER SCALE SUBSIDENCE SHOULD RESULT IN AT LEAST SOME
DISSIPATION OF THE LO CLDS. DEPENDING ON THE DEGREE OF CLRG...THE
COOLER INTERIOR LOCATIONS OVER THE W HALF COULD SEE TEMPS FALL WELL
INTO THE 40S.

TUE THRU FRI...ANOTHER SHRTWV IS FCST TO SWING THRU THE UPR LKS ON
TUE UNDER NW FLOW ALOFT...SO WL MAINTAIN SOME LO CHC POPS. DURING
THE MID/LATE WEEK TIME...LARGER SCALE NW FLOW ALOFT IS PROGGED TO
PERSIST AROUND FAIRLY DEEP UPR TROF IN SE CANADA. THERE IS POOR
AGREEMENT AMONG THE LARGER SCALE GUIDANCE ON TIMING/TRACK OF THESE
FEATURES...SO WL HOLD ON TO MODEL CONSENSUS POPS. LOOKS LIKE THE
BEST CHC FOR DRY WX IS ON WED. TEMPS WL RUN BLO NORMAL DURING THE
LONGER TERM PERIOD.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 142 PM EDT FRI JUL 31 2015

A DISTURBANCE MOVING THROUGH IS LEADING TO ISOLATED-SCATTERED
SHOWERS ACROSS AND UPWIND OF THE AREA. THESE SHOWER WILL CONTINUE TO
DEVELOP NEAR KSAW OVER THE NEXT FEW HOURS AND WILL MOVE WARD KIWD
LATER THIS AFTERNOON/EARLY EVENING. INCLUDED VCSH AT BOTH THOSE
SITES SINCE CONFIDENCE IN PRECIPITATION OCCURRENCE AT THOSE SITES IS
LOW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 452 AM EDT FRI JUL 31 2015

A LOW SPINNING OVER SOUTHERN HUDSON BAY WILL SWEEP A SERIES OF
TROUGH ACROSS LAKE SUPERIOR THROUGH THIS WEEKEND. A TROUGH
MOVING ACROSS EASTERN LAKE SUPERIOR THIS MORNING WILL REINFORCE
WESTERLY WINDS OF 10-20KTS WITH A FEW GUSTS UP TO 25KTS. WINDS WILL
REMAIN IN THE 10-20KT RANGE THROUGH THE START OF THE WEEKEND. A
BROAD SURFACE TROUGH WILL MOVE ACROSS THE UPPER GREAT LAKES REGION
ON SUNDAY BEFORE HIGH PRESSURE FROM THE CANADIAN PRAIRIES GRADUALLY
MOVES INTO THE REGION FOR THE START OF NEXT WEEK.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KC
AVIATION...TITUS
MARINE...SRF



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