Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 181924
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
324 PM EDT MON AUG 18 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM EDT MON AUG 18 2014

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A FAIRLY STRONG
SHRTWV OVER THE NRN PLAINS DRIFTING TO THE ESE INTO NW MN DOWNSTREAM
OF A RDG OVER WRN CANADA AND TOWARD A SHRTWV RDG STRETCHING FM
HUDSON BAY TOWARD THE SE GREAT LKS ON THE WRN FLANK OF A DEEP TROF
OVER THE CNDN MARITIMES. THERE IS ALSO A WEAKER SHRTWV MOVING E THRU
THE UPR LKS AHEAD OF THE MAIN DISTURBANCE APRCHG MN...AND THIS
FEATURE ALONG WITH ACCOMPANING AXIS OF GREATER H85 THETA E ADVCTN/A
FAIRLY MOIST 12Z GRB RAOB /KINX 36C AND PWAT 1.64 INCH OR ALMOST 175
PERCENT OF NORMAL/ HAS BEEN THE FOCUS FOR SOME SCT-NMRS SHOWERS
MAINLY OVER CENTRAL CWA TODAY. BUT QUITE A CONTRAST JUST TO THE E
WITH THE 12Z APX RAOB DISPLAYING A MUCH DRIER PROFILE...KINX -12C
AND PWAT 0.66 INCH OR ONLY 75 PERCENT OF NORMAL. THIS DRIER/STABLE
AIRMASS HAS SLOWED THE PROGRESS OF THE SHOWERS INTO THE AREA ARND
NEWBERRY SO FAR. THERE ARE MORE NMRS SHOWERS/A FEW TS MOVING INTO
WRN LK SUP CLOSER TO THE TRAILING SHRTWV. OTRW...QUITE A BIT OF CLD
COVER HAS LIMITED THE DIURNAL RISE OF TEMP AND DESTABILIZATION IN
THE ABSENCE OF STEEP LAPSE RATES SHOWN ON EVEN THE MOISTER 12Z GRB
RAOB...SO TS HAVE BEEN FEW AND FAR BTWN. BUT SOME HEAVY RAINS HAVE
FALLEN UNDER THE STRONGER SHOWERS WITH THE HIER PWAT/DEEPER MSTR.

MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS RELATED TO THE TWO
DISTURBANCES THAT ARE MOVING THRU MN/THE UPR LKS.

LATE TODAY/TNGT...AS TROF OVER QUEBEC SLOWLY EXITS TO THE E...LEAD
SHRTWV MOVING THRU THE UPR LKS/ACCOMPANYING AXIS OF H85 THETA E
ADVCTN WL DRIFT TO THE E AND BRING SOME SHOWERS TO THE FAR ERN CWA
BY 00Z. ALTHOUGH THERE MAY BE ONLY SOME ISOLD/SCT SHOWERS OVER WRN
UPR MI WITH SOME H7-5 DRYING MOST OF TODAY...MORE NMRS SHOWERS/SOME
TS ASSOCIATED WITH THE STRONGER SHRTWV MOVING INTO MN WL ARRIVE OVER
THE FAR W ARND 00Z TOWARD AREA WHERE THE 12Z NAM/REGIONAL CNDN MODEL
SHOW HIER MUCAPE UP TO ABOUT 750 J/KG NEAR IWD. BUT SINCE THE MN
SHRTWV WL BE TENDING TO DIG ESEWD THRU THE NGT...THE 12Z NAM/
REGIONAL CNDN MODEL INDICATE THE MORE NMRS SHOWERS WL IMPACT WI
CLOSER TO MORE VIGOROUS H85-7 MSTR CNVGC/HIER MUCAPE IN THE 500-
1000J/KG THAT WL BE CONFINED TO WI. SO WL MAINTAIN THE HIEST LIKELY
POPS TOWARD THE WI BORDER... ALONG WITH THE TS CHANCES PER ABSENCE
OF FCST MUCAPE AOA 200 J/KG FARTHER N. BUT DEEP LYR QVECTOR CNVGC/
DEEP SATURATION ON FCST SDNGS ON THE CYC SIDE OF SHRTWV TRACK
JUSTIFIES AT LEAST 50-60 POPS OVER THE ENTIRE CWA EVEN IF THE BETTER
FORCING/INSTABILITY HOLD TO THE SW. EXPECT LTL DIURNAL TEMP DROP
WITH LOTS OF CLDS/LINGERING HIER PWAT IN THE 1.50-1.75 RANGE. ADDED
SOME PATCHY FOG...ESPECIALLY IN AREAS OVER THE CENTRAL THAT WL
EXPERIENCE UPSLOPE SE FLOW.

TUE...EXPECT CONTINUED SCT-NMRS SHOWERS AND A FEW TS AS THE SHRTWV/
SFC LO REFLECTION SLIDE ESEWD THRU NRN WI AND MAINTAINS DEEP MSTR...
CYC FLOW AND DEEP LYR QVECTOR CNVGC OVER UPR MI. FCST WL SHOW
DIMINISHING POPS IN THE AFTN OVER THE W WITH PASSAGE OF SHRTWV TO
THE E AND ARRIVAL OF SOME DNVA/DEEP LYR QVECTOR DVGC AFT 18Z. FOG IN
THE MRNG OVER MAINLY THE CENTRAL ZNS WL DSPT SLOWLY WITH DIURNAL
HEATING LIMITED BY EXTENSIVE CLD COVER.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM EDT MON AUG 18 2014

THE START OF THE PERIOD WILL BE A WET ONE AS AN UPPER WAVE OVER WRN
LAKE SUPERIOR AT 12Z TUE CLOSES OFF AS IT MOVES INTO THE WRN U.P. BY
18Z TUE. THE UPPER LOW WILL THEN SLOW DOWN...FINALLY LEAVING THE
AREA LATER ON WED. THE SFC LOW WILL BE SOMEWHERE OVER NRN WI OR
ALONG THE WI/MI BORDER AT 12Z TUE AND WILL SLOWLY SHIFT E INTO TUE
NIGHT BEFORE MORE QUICKLY MOVING SE ON WED. PWATS ON TUE WILL BE
BETWEEN 1.5 AND 1.7 INCHES /NORMAL IS AROUND AN INCH/...WHICH WHEN
COMBINED WITH THE FORCING FROM THE UPPER LOW/CYCLONIC FLOW AND
UPSLOPE FLOW OFF THE GREAT LAKES IN SPOTS /ESPECIALLY OVER WRN UPPER
MI/...WILL RESULT IN DECENT PRECIPITATION PRODUCTION. THINK THAT
SOME SPOTS COULD SEE EASILY OVER AN INCH OF PRECIP ON TUE/EARLY TUE
NIGHT...DEPENDING ON SMALLER SCALE FEATURES THAT ARE NOT ENTIRELY
CLEAR AT THIS POINT. WHILE IT IS HARD TO GET TOO SPECIFIC ON
HEAVIEST PRECIP PLACEMENT/TIMING...THINK THAT MOST OF THE CWA WILL
SEE PERIODS OF RAIN TUE INTO TUE NIGHT...SO WILL INCREASE POPS TO
LIKELY IN MOST PLACES. WILL LEAVE THUNDER CHANCES TO A MINIMUM...BUT
WILL HAVE A CHANCE OF THUNDER OVER SCENTRAL AND WRN UPPER MI WHERE
CAPES WILL BE A BIT HIGHER AT AROUND 200J/KG DURING THE DAY TUE.
WITH THICK CLOUD COVER...MAX TEMPS ON TUE WILL BE IN THE MID 60S TO
LOW 70S...OR 5 TO POSSIBLY 10 DEGREES BELOW NORMAL.

WED WILL SEE DECREASING PRECIP CHANCES AS THE SYSTEM MOVES SE...BUT
DO LINGER CHANCE POPS THROUGH THE MORNING. BEHIND THE SYSTEM...AN
UPPER RIDGE DEVELOPS OVER THE REGION...WHICH WILL KEEP THINGS A BIT
DRIER THAN EARLY IN THE WEEK. MODELS DO POINT TO PRECIPITATION
OCCURRING ALONG A WARM FRONT THAT MOVES THROUGH THU INTO THU
NIGHT...BUT IT IS UNCERTAIN HOW MUCH PRECIP WILL MAKE IT INTO THE
CWA AS THE FRONT MOVES UNDER THE UPPER RIDGE AND INTO THE DRIER AIR.
WILL HAVE CHANCE POPS THU INTO THU NIGHT...AND SOME LINGERING POPS
INTO FRI.

UNCERTAINTY IS GREATER GOING INTO THE WEEKEND AS MODELS SHOW QUITE A
BIT OF VARIABILITY /RUN TO RUN AND MODEL TO MODEL/ WITH THE
STRENGTH/TRACK/TIMING OF A LOW PRESSURE SYSTEM MOVING SOMEWHERE IN
OR NEAR THE REGION. WHILE MODELS DO APPEAR TO AGREE WITH QPF ON
SAT/SAT NIGHT...THEY DO NOT AGREE ON THE REASON FOR THAT QPF...SO
CONFIDENCE IS LOWER THAN IT WOULD SEEM BY JUST LOOKING AT QPF.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 123 PM EDT MON AUG 18 2014

ALTHOUGH THE SPECIFICS ARE FAR FROM CLEAR...EXPECT IFR CONDITIONS TO
PREDOMINATE THIS FCST PERIOD WITH DEEP MSTR/SCT TO AT TIMES NMRS
SHRA OVER THE UPR LKS ASSOCIATED WITH DISTURBANCE MOVING SLOWLY
ESEWD THRU MN. BEST CHC FOR THE LOWER LIFR...AND POSSIBLY VLIFR...
CONDITIONS WL BE LATER TNGT/EARLY TUE IN THE PRESENCE OF NOCTURNAL
COOLING WHEN THE TAF SITES EXPERIENCE UPSLOPE FLOW.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 322 PM EDT MON AUG 18 2014

ADDED SOME FOG TO THE FORECAST THRU MUCH OF TUE OVER MAINLY THE
CENTRAL LAKE GIVEN ARRIVAL OF DEEPER MOISTURE AND EXPECTED AREA OF
LOWER TEMPERATURES NEAR THE LINGERING COOLEST DEEPER WATER.
OTHERWISE... EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRESSURE 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...TITUS
AVIATION...KC
MARINE...KC



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