Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 252348
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
748 PM EDT FRI JUL 25 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 343 PM EDT FRI JUL 25 2014

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A WNW FLOW ALF
OVER THE UPR LKS BTWN DEEP CLOSED LO OVER NRN QUEBEC AND SHRTWV RDG
AXIS EXTENDING NNEWD INTO MN/NW ONTARIO FM CENTER OF HIER HGTS OVER
THE SRN ROCKIES. ALTHOUGH SLOW INFLUX OF MOISTER AIR IN THE GENERAL
SW FLOW BTWN SFC/H85 HI OVER THE MID ATLANTIC STATES AND LOWER MSLP
IN THE NRN PLAINS ASSOCIATED WITH A DEEP CLOSED LO IN SRN
SASKATCHEWAN THAT IS RIDING OVER THE RDG CENTERED IN THE SRN ROCKIES
HAS ALLOWED FOR A GOOD DEAL OF CLDS/A FEW SHOWERS OVER MAINLY THE W
HALF OF THE CWA TDAY...MAIN FOCUS FOR HEAVIER PCPN HAS BEEN WELL TO
THE SW CLOSER TO SHARP H85 WARM FNT STRETCHING FM THE DAKOTAS INTO
THE MID MS RIVER VALLEY. HI STABILITY SHOWN ON THE 12Z INL RAOB AND
ESPECIALLY THE GRB RAOB...WHICH DEPICTS A SHARP INVRN ARND H75...HAS
TENDED TO LIMIT THE INTENSITY AND COVERAGE OF THE SHOWERS THAT HAVE
IMPACTED UPR MI. OVER THE ERN CWA...VERY DRY/STABLE AIRMASS SHOWN ON
THE 12Z APX RAOB HAS ALLOWED FOR MORE SUNSHINE. BUT TO THE W...MORE
SHOWERS ARE PRESENT IN NE MN/WRN LK SUP IN AREA OF HIER H85 THETA E
ADVCTN IN ADVANCE OF A WEAK SHRTWV MOVING E ALONG THE CNDN BORDER
ARND CLOSED LO IN SASKATCHEWAN. BUT EWD PUSH OF DRIER AIR IN THE NRN
PLAINS IS TENDING TO LIMIT THE OVERALL COVERAGE OF THESE SHOWERS AS
WELL.

MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE PCPN CHCS ASSOCIATED
WITH SHRTWV NOW MOVING ALONG THE CNDN BORDER.

LATE TDAY/TNGT...EXPECT AREA OF SHOWERS NOW IN NE MN AND A FEW
TS...THE POTENTIAL OF WHICH WL BE LIMITED BY PERSISTENT HIER MID LVL
STABILITY DEPICTED BEST ON THE GFS FCST SDNGS...TO SPREAD W-E INTO
UPR MI WITH AREA OF POSITIVE H85 THETA E ADVCTN THAT WL LIFT PWAT UP
TO ARND 1.5 INCHES/AXIS OF SOME H85-5 QVECTOR CNVGC IN ADVANCE OF
SHRTWV NOW TRACKING E ALONG THE CNDN BORDER. BUT ARRIVAL OF DRY AIR
NOW IN THE NRN PLAINS WL TEND TO DIMINISH THE POPS LATER EVEN THOUGH
THERE ARE HINTS A 2ND SHRTWV MIGHT FOLLOW INTO THE UPR LKS. FCST
LARGE SCALE QVECTOR DVGC OVER THE W LATE INDICATES THE DRYING WL
OVERCOME ANY PVA ASSOCIATED WITH THIS TRAILING SHRTWV. GOING FCST
POPS ARE IN PRETTY GOOD SHAPE AND NEED ONLY SMALL ADJUSTMENTS.
DESPITE THE MID LVL DRYING LATE...DVLPG LO CLDS WL LIMIT THE DIURNAL
TEMP FALL.

SAT...ANY LINGERING MRNG SHOWERS OVER MAINLY THE NE CWA WL END WITH
ARRIVAL OF DRIER AIR ALF THAT WL DEPRESS PWAT TO 0.75-1.0 INCH/DNVA
AND DEEP LYR QVECTOR DVGC AHEAD OF SHRTWV RDG TRAILING THE DEPARTING
2ND SHRTWV. WITH MRNG LO CLDS GIVING WAY TO MORE SUNSHINE AND FCST
H85 TEMPS AS HI AS 17-18C OVER THE W BY 00Z SUN...EXPECT MAX TEMPS
TO RISE INTO THE 80S AWAY FM THE MODERATING INFLUENCE OF THE GREAT
LKS. GIVEN THE MID LVL DRYING/POTENTIAL FOR DEEP MIXING AND NEAR
ADIABATIC LLVL LAPSE RATES...PREFER THE HIER END OF GUIDANCE FOR MAX
TEMPS...AT LEAST OVER THE INTERIOR W HALF. SOME OF THE HIER RES
MODELS...MAINLY THE 12Z NAM AND REGIONAL CNDN MODEL...DO INDICATE
THIS DAYTIME HEATING WL TRIGGER SOME SHOWERS/TS OVER THE ERN CWA IN
THE AFTN WITH CONVERGING LK BREEZES OFF LKS SUP/MI UNDER SOMEHWAT
LOWER HGTS. THE MAIN LIMITING FACTOR FOR THE DLPMNT OF THESE LK
BREEZE SHOWERS/TS WL BE THE DRYING ALF THAT IS FCST TO MIX TO THE
SFC WITH THE DAYTIME HEATING. IN FACT...DEEP MIXING ON THE GFS/NAM
FCST SDNGS HINT SFC DEWPTS OVER THE INTERIOR W HALF COULD MIX OUT AS
LO AS 45-50 LATE IN THE DAY...WITH KINX DROPPING TO 15-20. THE NAM
FCST SDNG FOR NEWBERRY AT 18Z SHOWS SBCAPE ARND 2K G/KG FOR SFC T/TD
OF 75/65. PREFER THE MORE CONSERVATIVE GFS FCST FOR SFC T/TD OF
75/60 AND SBCAPE CLOSE TO 700 J/KG. DESPITE THE LIMITATION OF THE
LARGE SCALE DRYING...WL MAINTAIN SOME LO CHC POPS OVER THE ERN CWA
TO ACCOUNT FOR THE LK BREEZE CNVGC.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 407 PM EDT FRI JUL 25 2014

COOL SUMMER PATTERN PERSISTS AS LARGE SCALE TROUGHING IS FORECAST TO
CONTINUE THROUGH DAYS 7-10. TEMPERATURES REMAIN BELOW NORMAL WITH
THE COOLEST DAYS EXPECTED MONDAY AND TUESDAY AS CORE OF UPPER LOW
AND COLD AIR MOVES ACROSS GREAT LAKES. MAX TEMPS BOTH DAYS LIKELY
WILL END UP AT LEAST 10 DEGREES BELOW NORMAL. NORMAL HIGHS THIS TIME
OF YEAR ARE IN THE MID 70S TO LOW 80S. MIN TEMPS WILL BE 5 TO 10
DEGREES BELOW NORMAL. NORMAL MIN TEMPS ARE IN THE LOW TO MID 50S.
OVERALL THIS PATTERN LOOKS DRY THROUGH THE NEXT COUPLE WEEKS PER THE
MEDIUM RANGE MODELS AND LATEST CPC OUTLOOKS.

BEST SHOT OF RAIN IS LATER SATURDAY NIGHT THROUGH SUNDAY AS UPPER
LOW AND STRONGER SHORTWAVE CURRENTLY OVER SOUTHERN SASKATCHEWAN
MOVES ACROSS WITH ASSOCIATED DEEP LAYER Q-VECTOR CONVERGENCE.
PASSAGE OF SHORTWAVE OCCURS AS THE INITIAL STRONG SFC-H85 COLD FRONT
IS CROSSING THE UPPER GREAT LAKES. MAIN ISSUE IS HOW FAST WILL THE
RAIN ARRIVE SATURDAY NIGHT AND ALSO IF THERE IS ANY POTENTIAL FOR
TSRA. SI/S BARELY BUMP BLO ZERO AND THAT IS FOCUSED ALONG THE WI
BORDER. HIGHEST POPS EXPECTED JUST TO NORTH OF UPPER LOW/SHORTWAVE
TRACK...MAINLY 09Z-21Z SUNDAY. TSRA CHANCES ARE THERE...BUT ARE
LIMITED TO A CHANCE AT BEST. UNLESS THE STORMS FORM EARLIER SATURDAY
EVENING WHEN DEEP SHEAR IS 30-40 KTS AND MLCAPE IS OVER 1000 J/KG...
DO NOT EXPECT ANY SEVERE STORMS SATURDAY NIGHT. INTO SUNDAY IT IS
POSSIBLE THAT IF THE SYSTEM SLOWS THERE WOULD BE INCREASED POTENTIAL
FOR SFC BASED TSRA SUNDAY AFTN. ATTM THOUGH LI/S BLO ZERO ARE
FORECAST TO STAY OVER WI AS STABLE COOL RAINY NORTH FLOW SHUNTS THE
GREATER INSTABILITY TO THE SOUTH. LOWERED TEMPS MORE ALONG LK
SUPERIOR ON SUNDAY...WITH UPR 50S TO AROUND 60 DEGREES. POINTS
FARTHER INLAND OVER SOUTHERN U.P. MAY BE ABLE TO REACH 70 DEGREES AT
LEAST BRIEFLY BEFORE CLOUDS THICKEN AND WIDESPREAD SHOWERS BEGIN.

SHOULD NOTE THAT THE STRONGER NORTH WINDS AND HIGHER WAVES WILL
INCREASE SWIM RISK FOR BEACHES OF LK SUPERIOR MQT TO GRAND MARAIS
SUNDAY INTO MONDAY. IF THE AIR TEMPS REMAIN IN THE UPPER 50S OR
HIGHER...WOULD NEED A BEACH HAZARD STATEMENT TO HIGHLIGHT THE RISK
EITHER FOR SUNDAY OR MONDAY OR POSSIBLY BOTH DAYS. ULTIMATELY WILL
DEPEND ON THE EXPECTED WEATHER FOR THE DAY.

BEYOND SUNDAY...UPPER TROUGH IN THE VCNTY COUPLED WITH INDIVIDUAL
SHORTWAVES AND AREAS OF DEEPER MOISTURE DROPPING ACROSS THE AREA
WILL COMBINE WITH DAYTIME HEATING/INSOLATION TO PRODUCE ISOLD-SCTD
SHOWERS...MAINLY DURING AFTN AND EVENING HOURS OF TUESDAY AND
WEDNESDAY. GRADUAL RISING HEIGHTS RESULT IN LESS CYCLONIC LOW-LEVEL
FLOW BY THURSDAY AND THERE IS ALSO LESS DEEP MOISTURE BY THAT POINT.
EXPECT THE CHANCES OF DIURNAL SHOWERS TO DIMINISH BY LATE THIS WEEK
AS TEMPS BEGIN TO WARM UP AGAIN. JUST ENOUGH MLCAPE DURING THE AFTN
FAR INLAND TO PUT KEEP SMALL TSRA CHANCES AS WELL WITH THE SHRA. MEAN
WINDS FM NORTH TO SOUTH RESULT IN GREATEST CHANCES FOR RAIN MOST DAYS
FARTHEST INLAND FROM THE MODERATION/STABILIZING INFLUENCE OF LK
SUPERIOR.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 743 PM EDT FRI JUL 25 2014

A MOIST LLVL SW FLOW COMBINED WITH AN UPPER DISTURBANCE MOVING ACROSS
THE AREA HAS RESULTED IN SCT SHRA ACROSS NCNTRL UPPER MI EARLY THIS
EVENING. MUCH OF THIS SHRA ACTIVITY WILL REMAIN MOSTLY NORTH OF THE
TAF SITES THIS EVENING SO WL ONLY INCLUDE VCSH IN THE TAFS. WITH SOME
DRYING ALF LATE TNGT THAT WL END THE SHOWERS...EXPECT IFR CONDITIONS
TO DVLP IN THE PRESENCE OF DIURNAL COOLING. LIFR CONDITIONS ARE NOT
OUT OF THE QUESTION. THE ARRIVAL OF DRIER AIR AND DAYTIME WL RESULT
IN IMPROVEMENT TO VFR ON SAT. THIS PROCESS WL BE SLOWEST AT CMX WITH
AN UPSLOPE NW WIND AND AT SAW WHERE A DEVELOPING N WIND COULD CAUSE
MVFR CLOUDS TO LINGER A BIT LONGER. &&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT FRI JUL 25 2014

EXPECT WINDS UNDER 15 KTS THRU SAT NIGHT WITH RELATIVELY WEAK PRES
GRADIENT DOMINATING THE UPPER LAKES. STRONGER N WINDS UP TO 20-25
KTS EXPECTED SUN INTO MON AS COOLER AIR INVADES THE AREA UNDER
TIGHTER GRADIENT BETWEEN HI PRES MOVING INTO THE NORTHERN PLAINS AND
LO PRES OVER THE SE GREAT LAKES. WINDS WILL DIMINISH ON TUE AND BACK
TOWARD THE W WITH CLOSER APPROACH OF HI PRES FROM THE PLAINS.
&&

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

$$

SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...TITUS/JLA





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