Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 KMKX 220349
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1049 PM CDT TUE APR 21 2015

.UPDATE...


&&

.AVIATION/06Z TAFS/...

MAINLY VFR. HOWEVER SOME MVFR CIGS/VSBYS IN SCATTERED
PRECIPITATION INTO THE EARLY MORNING...WITH THE POTENTIAL FOR A
RAIN/SNOW MIX ACROSS THE AREA. ANY PRECIP AMOUNTS WILL BE
LIGHT...THOUGH PRECIP MAY BRIEFLY CAUSE REDUCTIONS IN VSBYS AND
CIGS. AFTER A BRIEF LULL...WINDS WILL PICK UP AGAIN BEHIND A
TROUGH THAT WILL MOVE ACROSS SOUTHEAST WISCONSIN BY 09Z OR 10Z.
WEST TO NORTHWEST WINDS WILL REMAIN GUSTY WEDNESDAY.

&&

MARINE...

A SMALL CRAFT ADVISORY IN EFFECT THROUGH THE DAY WEDNESDAY.
WINDS HAVE WEAKENED A LITTLE THIS EVENING...BUT ARE EXPECTED TO
REACH SMALL CRAFT ADVISORY CRITERIA AGAIN EARLY WEDNESDAY MORNING
BEHIND A TROUGH AXIS. THE TIGHT SURFACE PRESSURE GRADIENT BEHIND
A LARGE SCALE LOW PRESSURE SYSTEM NORTHWEST OF LAKE SUPERIOR...
ALONG WITH A DEEP WELL-MIXED BOUNDARY LAYER WILL KEEP WINDS
GUSTY. WINDS SHOULD GUST NEAR 30 KNOTS AGAIN LATE TONIGHT AND
WEDNESDAY.


&&

.PREV DISCUSSION... /ISSUED 315 PM CDT TUE APR 21 2015/

SHORT TERM...TONIGHT THROUGH FRIDAY

TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE HIGH.

AN EXTENSIVE UPPER LEVEL LOW PRESSURE SYSTEM...WITH AN ASSOCIATED
500 MB SHORTWAVE TROUGH...WILL PERSIST OVER THE NORTHERN GREAT
LAKES/ONTARIO CANADA PROVINCE. CHANCES OF A WINTRY MIX BEHIND THIS
LOW PRESSURE SYSTEM WILL PERSIST TONIGHT UNTIL JUST BEFORE
MIDNIGHT...ALTHOUGH PRECIPITATION WILL BE SCATTERED. THE LOW WILL
SLOWLY MOVE OFF TO THE NORTHEAST...ALLOWING THE PRECIPITATION TO
DIMINISH BY EARLY WEDNESDAY MORNING. SFC PRESSURE GRADIENT BEHIND
THIS LOW PRESSURE SYSTEM LOOKS TO STAY TIGHT ACROSS SOUTHERN
WISCONSIN TONIGHT...KEEPING GUSTY WEST TO NORTHWEST WINDS IN THE
AREA. WINDS SHOULD WEAKEN OVERNIGHT AS THE SFC PRESSURE GRADIENT
WEAKENS.

WEDNESDAY SHOULD BE DRIER THAN TUESDAY AS BETTER FORCING WILL MOVE
OFF TO THE NORTHEAST. HOWEVER...WINDS WILL RAMP UP AGAIN FROM THE
NORTHWEST WEDNESDAY. TEMPERATURES WILL REMAIN COOL AS 925 MB
TEMPERATURES WILL BE IN THE NEGATIVE SINGLE DIGITS OVERNIGHT. LOWS
TONIGHT WILL BE IN THE LOWER 30S...AND EVEN SOME UPPER 20S...ACROSS
THE FORECAST AREA. SMALL CHANCES OF RAIN/SNOW WILL RETURN WEDNESDAY
AFTERNOON ACROSS OUR NORTHERN TIER OF COUNTIES AS LOW LEVEL LAPSE
RATES WILL STEEPEN ONCE AGAIN...ACCORDING TO NAM BUFKIT SOUNDINGS.

WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM.

BROAD CYCLONIC FLOW PREVAILS ALOFT AS A CLOSED UPPER LOW SLOWLY
MIGRATES FROM EASTERN ONTARIO INTO NEW ENGLAND. AS MID-LEVEL HEIGHTS
SLOWLY RISE...WEAK SFC HIGH PRESSURE RIDGE SHIFTS EAST INTO THE
AREA FROM THE CENTRAL PLAINS ON THURSDAY. DESPITE DRIER AIR
WORKING IN...HELD ON TO SOME CLOUD COVER IN THE NORTHEAST CWA FOR
THURSDAY WITH SHEAR AXIS NEARBY AND LOW-LEVEL RH VALUES REMAINING
HIGH THROUGH AROUND 18Z. THEREAFTER...REST OF THE PERIOD LOOKS
COOL AND DRY WITH NORTHWESTERLY FLOW ALOFT.

LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE
LOW.

BOTH ECMWF AND GFS AGREE ON EJECTING A SHORTWAVE OUT OF THE
CENTRAL PLAINS FRIDAY NIGHT...AND INTO NORTHERN ILLINOIS ON
SATURDAY. LAST NIGHT/S ECMWF SOLUTION HAD THE ASSOCIATED SURFACE
LOW FARTHER NORTH...RESULTING IN MORE PRECIPITATION ACROSS THE
CWA FRIDAY NIGHT AND SATURDAY. THE 12Z RUN HAS BACKED
OFF CONSIDERABLY...TRACKING THE SURFACE LOW FARTHER SOUTH ACROSS
THE OHIO VALLEY. THIS IS MORE IN LINE WITH THE 12Z GFS SOLUTION.
USED BLENDED CONSENSUS POPS FOR THE PERIOD...BRINGING CHANCE POPS
INTO THE SOUTHERN CWA FRIDAY NIGHT AND KEEPING THEM THROUGH
SATURDAY AFTERNOON. THERMAL PROFILES SUPPORT A POSSIBLE RAIN-SNOW
MIX DURING THE MORNING HOURS ON SATURDAY...BUT OVERALL
PRECIPITATION AMOUNTS APPEAR MEAGER AT BEST.

SUNDAY LOOKS QUIET AND DRY WITH WEAK SURFACE RIDGING IN CONTROL.
AN UPSTREAM SHORTWAVE...INITIALLY OVER THE NORTHERN ROCKIES...WILL
ADVANCE INTO THE UPPER MISSISSIPPI VALLEY ON MONDAY AND TREK
EASTWARD ON TUESDAY. MODEL SOLUTIONS DIFFER FOR MONDAY AND
TUESDAY...WITH THE GFS EJECTING AN OPEN-WAVE TROUGH SOUTHEASTWARD
INTO IOWA AND MISSOURI. PREVIOUS ECMWF RUN CARVED OUT A CLOSED LOW
OVER EASTERN MINNESOTA AND WESTERN WISCONSIN...WHILE THIS
MORNING/S RUN HAS A COMPLETELY DRY SOLUTION WITH WEAK MID-LEVEL
RIDGING OVER THE REGION. NEEDLESS TO SAY...CONFIDENCE IN THIS
PERIOD IS RATHER LOW...SO AGAIN WENT WITH A CONSENSUS MODEL BLEND
FOR POPS.

AVIATION/00Z TAFS/...LOW END VFR CIGS WILL CONTINUE THIS EVENING AS
A LOW LEVEL STRATUS DECK WILL PERSIST OVER THE REGION...THANKS TO AN
EXITING LARGE SCALE LOW PRESSURE SYSTEM. SOME SCATTERED
PRECIPITATION IS POSSIBLE THIS EVENING...WITH THE POTENTIAL FOR A
RAIN/SNOW MIX ACROSS THE AREA. ANY PRECIP AMOUNTS WILL BE
LIGHT...THOUGH PRECIP MAY BRIEFLY CAUSE REDUCTIONS IN VSBYS AND
CIGS. WEST WINDS WILL REMAIN GUSTY THIS EVENING UNTIL TAPERING OFF
BY 03Z AS A TIGHT SFC PRESSURE GRADIENT WEAKENS LATER THIS
EVENING.

MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT UNTIL 03Z TONIGHT. A
TIGHT SFC PRESSURE GRADIENT BEHIND A LARGE SCALE LOW PRESSURE SYSTEM
EXITING THE REGION...ALONG WITH A DEEP WELL-MIXED BOUNDARY LAYER
MIXED UP TO 800 MB WILL KEEP WINDS GUSTY. WINDS SHOULD GUST NEAR 30
KTS...WITH A FEW GUSTS UP TO 35 KTS OVER OUR NEARSHORE WATERS EARLY
THIS EVENING. THE WINDS WILL WEAKEN LATER THIS EVENING AS THE SFC
PRESSURE GRADIENT WEAKENS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR LMZ643>646.

&&

$$

UPDATE...HENTZ
TONIGHT/WEDNESDAY AND AVIATION/MARINE...JTS
WEDNESDAY NIGHT THROUGH TUESDAY...SPM



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