Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KMQT 241139
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
739 AM EDT SUN AUG 24 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 524 AM EDT SUN AUG 24 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE ROCKIES
WITH DOWNSTREAM RIDGE EXTENDING N THRU THE GREAT LAKES. IN THE
TROF...A VIGOROUS SHORTWAVE WAS LIFTING THRU WY INTO ERN MT/FAR WRN
DAKOTAS. AHEAD OF THIS MAIN FEATURE...ANOTHER SHORTWAVE WAS LIFTING
THRU THE ERN DAKOTAS INTO MANITOBA. SHRA/TSRA HAVE BEEN LINED UP
WITH THIS WAVE ACROSS THE ERN DAKOTAS/WRN MN. LOW-LEVEL JET AHEAD OF
FEATURE HAS ALSO GENERATED SHRA FARTHER E IN NE MN INTO ADJACENT NRN
ONTARIO. CLOSER TO HOME...IT HAS BEEN A QUIET NIGHT. THERE HAVE BEEN
SOME SPRINKLES AT TIMES OVER THE W HALF OF UPPER MI AND PERHAPS A
BRIEF -SHRA OVER THE FAR W...PROBABLY TIED TO ERN EDGE OF LOW-LEVEL
JET. OTHERWISE...MOSTLY CLOUDY SKIES HAVE BEEN THE RULE OVER THE W
AND PARTLY CLOUDY E.

TODAY...SCT SPRINKLES/PERHAPS A -SHRA OVER THE W WILL END THIS
MORNING AS LOW-LEVEL JET LIFTS N. OTHERWISE...LOOKS LIKE A DRY DAY
IS ON THE WAY. APPROACHING COLD FRONT TODAY WILL REMAIN WELL W OF
UPPER MI WITH THE ROUGHLY N-S ORIENTED FRONT ONLY HALFWAY ACROSS MN
BY 00Z THIS EVENING. FCST SOUNDINGS ALSO SUGGEST A CAPPED
ENVIRONMENT WITH 850MB THERMAL RIDGE NOSING INTO THE AREA. SINCE
THERE IS ESSENTIALLY NO FORCING WITH MID/UPPER RIDGE HOLDING (NO
HEIGHT FALLS)...WILL CARRY DRY WEATHER THRU THE AFTN HRS. MAY BE
ABLE TO GET A FEW MORE BREAKS IN THE CLOUDS TODAY TO BOOST TEMPS
SOME. FCST REFLECTS THIS IDEA WITH MAX TEMPS MOSTLY IN THE UPPER
70S/LWR 80S. WILL BE A LITTLE COOLER IF CLOUDS CONTINUE TO BE MORE
PERSISTENT.

AS COLD FRONT PROGRESSES EASTWARD TONIGHT...HEIGHT FALLS SPREADING
OVERTOP ABUNDANT INSTABILITY (MLCAPE OF 1500-3000J/KG) SHOULD YIELD
RAPID TSTM DEVELOPMENT ALONG FRONT THIS EVENING IN MN. HIGH RES NAM
WINDOW...NCEP WRF ARW AND NMM AS WELL AS NSSL WRF ALL LOOK QUITE
REASONABLE WITH EXPECTATIONS. THE BIG QUESTION IS HOW THE STORMS
HOLD TOGETHER WHILE MOVING E INTO UPPER MI DURING THE NORMAL
NIGHTTIME DOWNWARD MLCAPE CYCLE. ALSO IN THIS CASE...DEEP LAYER
FORCING IS WEAK WHICH MAY FURTHER HASTEN A WEAKENING TREND DURING
THE NIGHT. AT THIS POINT...THE W HAS THE BEST CHC OF SEEING
CONVECTION GIVEN ARRIVAL EARLIER IN THE NIGHT. WITH DEEP LAYER SHEAR
INCREASING TO 30-40KT...STRONG STORMS AND PERHAPS AN ISOLD SVR ARE
POSSIBLE OVER THE FAR W IF STORMS ARRIVE EARLY ENOUGH BEFORE
INSTABILITY BEGINS DIMINISHING. WILL CARRY SHRA/TSRA CHANCES
EASTWARD DURING THE NIGHT...BUT WITH A GRADUAL LOWERING OF POPS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 354 AM EDT SUN AUG 24 2014

AFTER A VERY CLOUDY PERIOD OVER THE UPPER GREAT LAKES REGION OVER
THE LAST 7-9 DAYS...EXPECT A TRANSITION TO DRIER...COOLER AND MORE
SUNSHINE FOR THE MIDDLE OF THE WORK WEEK.

THE TRANSITION WILL BE LED BY A COLD FRONT THAT WILL BE MOVING
THROUGH THE CWA MONDAY MORNING AND EARLY AFTERNOON. THIS FRONT IS
ASSOCIATED WITH 1002MB LOW PRESSURE SYSTEM THAT WILL BE MOVING FROM
NEAR LAKE WINNIPEG ON MONDAY MORNING TO JAMES BAY ON MONDAY NIGHT.
AS THIS OCCURS...AN OCCLUDED FRONT WILL STRETCH EAST INTO NORTHERN
ONTARIO AND THEN A COLD FRONT STRETCHING SOUTH ACROSS WEST/CENTRAL
LAKE SUPERIOR AND UPPER MICHIGAN AROUND 12Z ON MONDAY. EXPECT
SHOWERS AND THUNDERSTORMS TO BE ONGOING MONDAY MORNING ALONG THE
FRONT AND SHIFTING EAST THROUGH THE MORNING AND EARLY AFTERNOON
HOURS. CURRENT FORECAST CALLS FOR THE FRONT AND ASSOCIATED
SHOWERS/THUNDERSTORMS TO BE EXITING THE EASTERN CWA TOWARDS THE LATE
AFTERNOON. WHILE THERE IS HIGH CONFIDENCE ON THE TIMING OF THE COLD
FRONT MOVING THROUGH (ALTHOUGH 00Z NAM HAS SLOWED THE FRONT
DOWN A FEW HOURS)...THE AMOUNT OF SHOWERS/THUNDERSTORMS ALONG THE
FRONT IS UNCERTAIN DUE TO SEVERAL LIMITATIONS. THESE LIMITATIONS
INCLUDE THE TIME OF DAY THE FRONT IS MOVING THROUGH...MUCH OF THE
FORCING FROM THE UPPER TROUGH AND SHORTWAVES WELL TO THE NORTHWEST
AND NEAR THE SURFACE LOW...ALONG WITH LIMITED MOISTURE AND WEAK
LAPSE RATES (AROUND 6C/KM) IN THE MID LEVELS. IN ADDITION...A NOSE
OF DRY AIR MOVING IN BETWEEN 900-700MB WILL HELP TO LIMIT ANY
SURFACE OR LOW LEVEL DEVELOPMENT. THESE FACTORS COMBINE TO KEEP POPS
ON THE LOW END OF CHANCES AS THE FRONT MOVES THROUGH AND THINK THE
BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS WILL COME FROM ANY
ONGOING STORMS MOVING INTO THE AREA FROM THE WEST TONIGHT AND TRYING
TO HOLD TOGETHER INTO MONDAY. IF SOMETHING CAN HOLD TOGETHER OR GET
GOING AS THE FRONT MOVES INTO THE EASTERN CWA MONDAY
AFTERNOON...THERE COULD BE STRONG THUNDERSTORMS WITH INSTABILITY ON
THE INCREASE (MU/ML CAPES INCREASING TO 500-1500 J/KG) AND 0-6KM
SHEAR VALUES AROUND 35KTS (OR 25-30KTS OF EFFECTIVE BASED OFF
POTENTIAL FOR ELEVATED THUNDERSTORMS). WEST OF THE COLD FRONT ON
MONDAY...WILL SEE MUCH DRIER AIR MOVING IN AND DEWPOINTS FALLING
INTO THE 50S AND SKIES BECOMING MOSTLY SUNNY.

THE LOW LEVEL WEDGE OF DRY AIR WILL REMAIN INTO MONDAY NIGHT
(PRODUCING PARTLY CLOUDY TO MOSTLY CLEAR SKIES) BEFORE 925-700MB
WINDS TURN MORE TO THE WEST AND EVENTUALLY WEST-NORTHWEST AS A
SECONDARY FRONT/TROUGH MOVES THROUGH. THERE COULD BE SOME SHOWERS
OVER THE SOUTHEAST CWA WITH THIS SECONDARY FRONT AND CLOSER TO
LINGERING MOISTURE FROM THE FIRST FRONT. BEHIND THE SECONDARY
FRONT...MODELS ARE INDICATING AN INCREASE IN 925-850MB MOISTURE
THAT WILL LEAD TO DIURNAL CLOUD DEVELOPMENT DURING THE DAY ON
TUESDAY OVER THE NORTH HALF OF THE LAND CWA EVEN THOUGH A HIGH
PRESSURE RIDGE (FROM A HIGH IN THE EASTERN DAKOTAS) WILL NOSE EAST
OVER THE WESTERN HALF OF THE CWA. FARTHER SOUTH...WOULD EXPECT
MOSTLY SUNNY SKIES AS THE COLD FRONT LOOKS TO SLIDE FAR ENOUGH SOUTH
INTO LOWER MICHIGAN AND SOUTHERN WISCONSIN TO KEEP ANY SHOWERS TO
THE SOUTH OF THE AREA. HIGH TEMPERATURES WILL BE ABOUT 10 DEGREES
COOLER ON TUESDAY THAN MONDAY...WITH HIGHS INT HE MID 70S OVER THE
SOUTHEAST HALF AND UPPER 60S OVER THE WEST NEAR LAKE SUPERIOR.

WITH THE FLOW BECOMING ZONAL FOR THE MIDDLE OF THE UPCOMING WORK
WEEK AND THE MAIN SHORTWAVES STAYING NORTH OF THE CWA AND MOVING
ACROSS NORTHERN ONTARIO...EXPECT THE HIGH PRESSURE TO FOLLOW THE
RIDGE EASTWARD WEDNESDAY INTO THURSDAY. THIS WILL PRODUCE DRY
WEATHER AND WITH 850MB TEMPS SLIGHTLY BELOW NORMAL (AROUND
9C) EXPECT HIGHS TO BE SIMILAR WITH RESPECT TO NORMAL. WILL MENTION
THAT THE SOUTH CENTRAL CWA COULD BE BRUSHED BY A FEW WEAK WAVES
RUNNING ALONG THAT FRONT TO THE SOUTH OF THE AREA ON TUESDAY
AND AGAIN THURSDAY...BUT WOULDN/T EXPECT MORE THAN A STRAY SHOWER.

THE HIGH PRESSURE RIDGE WILL BEGIN TO SLIDE EAST ON FRIDAY WHILE AN
UPPER TROUGH SEPARATED FROM THE NORTHERN STREAM FLOW SLIDES EAST
INTO THE CENTRAL PLAINS. THIS WAVE WILL DEVELOP A WEAK SURFACE LOW
IN THE CENTRAL PLAINS AND SLIDE EAST-NORTHEAST THROUGH THE GREAT
LAKES REGION FRIDAY AFTERNOON INTO FRIDAY NIGHT. 00Z GEM
IS CONSISTENT WITH PREVIOUS RUNS AND 00Z ECMWF ON A SLOWER
ARRIVAL WITH THE UPPER TROUGH AND SURFACE LOW...WHILE THE 00Z GFS
LOOKS TO HAVE CONVECTIVE FEEDBACK ISSUES IN THE CENTRAL PLAINS ON
MONDAY/TUESDAY EVENING WHICH SPEEDS UP THE UPPER TROUGH AND
PUSHES IT THROUGH 12-24HRS EARLIER. FEEL A GENERAL CONSENSUS AND
FOCUS TOWARDS THE ECMWF (AND THE MATCHING TIMING WITH THE GEM) IS A
GOOD MIDDLE POINT RIGHT NOW AND WILL FOLLOW THAT IDEA. THIS WAVE
WILL SHIFT EAST OF THE AREA ON SATURDAY AND LEAD TO DRY WEATHER.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 738 AM EDT SUN AUG 24 2014

MOIST UPSLOPE FLOW HAS BROUGHT A RETURN OF LIFR CIGS TO KCMX/KSAW.
THESE LOWER CLOUDS SHOULD SCATTER OUT WITH DAYTIME HEATING...
ALLOWING VFR CONDITIONS TO DEVELOP LATE THIS MORNING OR EARLY THIS
AFTN. DOWNSLOPE SE TO S WINDS AT KIWD SHOULD KEEP CONDITIONS VFR
THERE. COLD FRONT APPROACHING FROM THE W SHOULD SPREAD SHRA/TSRA
INTO WRN UPPER MI LATE THIS EVENING. INCLUDED A MENTION OF VCTS AT
KIWD. WITH LESS CONFIDENCE IN TSRA PERSISTING DUE TO DECREASING
INSTABILITY OVERNIGHT...DID NOT INCLUDE A MENTION OF THUNDER AT
KCMX/KSAW. UNDER UPSLOPE WINDS...KSAW SHOULD SEE A RETURN OF MVFR
CIGS TONIGHT...PERHAPS IFR LATE. OTHERWISE...CONDITIONS AT KIWD/KCMX
WILL DEPEND ON INTENSITY OF SHRA THAT OCCUR AT THOSE TERMINALS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 24 2014

FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU MON GIVEN
THE HUMID AIR MASS THAT CONTINUES TO LINGER OVER THE AREA. PASSAGE
OF A COLD FRONT MON WILL THEN WORK TO CLEAR OUT ANY FOG FROM W TO E
AS DRIER AIR FLOWS INTO THE UPPER LAKES. AHEAD OF THE COLD FRONT...E
TO SE WINDS WILL INCREASE SOME TODAY/TONIGHT. WINDS OF 15-25KT SHOULD
BE OBSERVED AT SOME OF THE HIGHER OBS PLATFORMS. IN THE WAKE OF THE
FRONT...WSW WINDS OF 15-25KT WILL DEVELOP OVER THE W HALF OF THE
LAKE ON MON. HIGH PRES WILL THEN SETTLE INTO THE UPPER LAKES LATE
TUE THRU THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.