665
FXUS63 KLOT 191107
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
607 AM CDT FRI APR 19 2019
SHORT TERM
331 AM CDT
THROUGH SATURDAY...
GOES DIFFERENTIAL WATER VAPOR RGB SHOWS DEEP TROUGH DIGGING SOUTH
TO THE NORTHWEST GULF OF MEXICO WITH A PAIR OF VORT MAX AND
ASSOCIATED JET STREAK STILL DIGGING SOUTH DOWN THE WESTERN FLANK
OF THE UPPER TROUGH. NUMERICAL GUIDANCE HAS THIS ENERGY CLOSING
OFF A MID-UPPER LEVEL LOW OVER THE SOUTHEAST U.S. TODAY BEFORE
BEGINNING A SLOW TURN NORTHEAST AND NORTHWARD TONIGHT INTO
SATURDAY. ASSOCIATED STRONG SURFACE LOW WILL TRACK NORTH INTO THE
OHIO VALLEY TONIGHT AND THE MEANDER AROUND A BIT SATURDAY BEFORE
THE ENTIRE SYSTEM BEGINS MOVING EAST.
SHOWERS ON THE NORTHWEST FLANK OF THE TROUGH, AFFECTING OUR
SOUTHEASTERN CWA, ARE EXPECTED TO PUSH EAST TODAY, BUT RAIN
CHANCES WILL INCREASE AGAIN SATURDAY MORNING AS THE ENTIRE DEEP
TROPOSPHERIC CIRCULATION WOBBLES WEST A BIT. SOUTHEAST CWA WILL
STAY SOCKED IN WITH CLOUD COVER TODAY WHILE SKIES LOOK TO CLEAR
FROM THE NORTHWEST THIS AFTERNOON. THE BIGGER IMPACT FROM THIS
SYSTEM WILL BE STRONG NORTHERLY WINDS TODAY THROUGH MUCH OF THE
DAY SATURDAY. FORECAST SOUNDINGS FOR THIS AFTERNOON SUPPORT GUSTS
WELL INTO THE 30 MPH RANGE WITH SOME GUSTS OVER 40 MPH A DECENT
BET. CAN'T RULE OUT BRIEFLY TAGGING WIND ADVISORY CRITERIA TODAY,
BUT FOR MOST PART SHOULD STAY JUST BELOW, SO NO HEADLINE PLANNED
AT THIS TIME.
THE STRONG NORTHERLY WINDS AND CLOUD COVER WILL KEEP TEMPS FROM
REBOUNDING MUCH FROM CURRENT READINGS NEAR THE LAKE AND IN
NORTHWEST INDIANA. POINTS FARTHER NORTHWEST, WHERE SKIES WILL
CLEAR OUT SOME TODAY SHOULD SEE TEMPS REBOUND INTO THE 50S THIS
AFTERNOON. TEMPS SHOULD MODERATE SOME SATURDAY WITH CLOUD COVER
AND STRONG NORTHERLY WINDS CONTINUING TO RESULT IN THE CHILLIEST
TEMPS OVER NORTHWEST INDIANA AND NEAR THE LAKE.
NO CHANGES PLANNED TO THE LAKESHORE FLOOD ADVISORY WITH NORTHERLY
GALES LIKELY TO RESULT IN VERY LARGE AND BATTERING WAVES. IN
ADDITION, LAKE LEVELS CONTINUE TO RISE (AND ARE APPROACHING LEVELS
NOT SEEN IN QUITE SOME TIME) AND WITH NORTHERLY WINDS DOWN THE
FULL FETCH OF THE LAKE SHOULD SEE WATER PILING UP (STORM SURGE)
OVER THE SOUTHERN PORTIONS OF THE LAKE. A BIT OF UNCERTAINTY WITH
RESPECT TO HOW LARGE THE WAVES GET DUE TO MARGINAL STABILITY
PROFILES IN THE MARINE LAYER RESULT IN A BIT OF UNCERTAINTY
REGARDING HOW LARGE WAVES WILL BUILD UP TODAY. NEARSHORE BUOYS
HAVE BEEN DEPLOYED, SO DAY SHIFT WILL BE ABLE TO SEE HOW WAVE
FORECAST IS VERIFYING, IF THE WAVE FORECAST VERIFIES THEN
LAKESHORE FLOOD ADVISORY WILL NEED TO BE EXTENDED FOR NORTHWEST
INDIANA INTO SATURDAY AND PERHAPS FOR COOK COUNTY AS WELL GIVEN
THE WIND TRAJECTORY.
- IZZI
LONG TERM
331 AM CDT
SATURDAY NIGHT THROUGH THURSDAY...
AS DEEP CYCLONE MOVES EAST OF THE REGION, LOOK FOR SOUTHERLY WINDS
AND STRONG WARM AIR ADVECTION TO RESULT IN ANOTHER BIG WARM UP IN
TEMPS SUNDAY. A BIT CONCERNED THE CUT OFF LOW COULD END UP BEING A
BIT SLOWER TO MOVE OUT THAN FORECAST, SO DIDN'T MAKE ANY CHANGES
TO THE BLENDED MODEL GUIDANCE, HOWEVER, SHOULD THE LOW MOVE OUT AS
FAST OR FASTER THAN FORECAST THAN SOME UPPER 70S TO NEAR 80 WEST
FOR HIGHS ARE POSSIBLE SUNDAY.
NEXT SHORTWAVE TROUGH WILL MOVE ACROSS THE REGION WITH SOME SHOWER
AND THUNDERSTORM CHANCES PERHAPS AS EARLY AS SUNDAY NIGHT, BUT
MORE LIKELY MONDAY INTO MONDAY NIGHT. SEASONABLY COOL AND DRY
WEATHER IS EXPECTED IN THE WAKE OF THAT SYSTEM MIDWEEK BEFORE
TEMPS BEGIN TO REBOUND LATE IN THE WEEK.
- IZZI
FIRE WEATHER
505 AM CDT
STRONG NORTHERLY WINDS TODAY, POSSIBLY GUSTING TO 40 MPH AT TIMES,
WILL RESULT IN A SOMEWHAT HEIGHTENED FIRE DANGER. THIS IS
PARTICULARLY THE CASE OVER WESTERN CWA WHERE LESS RAIN FELL AND
LOWER RH AND HIGHER TEMPS ARE EXPECTED TODAY DUE TO MORE SUNSHINE.
WHILE STRONG WINDS WILL OCCUR OVER EASTERN IL AND NORTHWEST IN,
COOLER TEMPS, WETTER FUELS, AND HIGH RH SHOULDN'T MITIGATE THE
FIRE DANGER.
SATURDAY WILL BE ANOTHER DAY OF STRONG NORTHERLY WINDS. MILDER
TEMPERATURES AND LOWER RELATIVE HUMIDITY VALUES COMPARED TO TODAY
WILL RESULT IN A GREATER FIRE DANGER. THE DRIEST FUELS ON SATURDAY
WILL AGAIN BE ACROSS NORTH CENTRAL IL, WHICH IS WHERE THE WINDS
ARE FORECAST TO BE LIGHTER. WINDS AND MIN RELATIVE HUMIDITY
VALUES COULD BOTH APPROACH RED FLAG WARNING CRITERIA OVER EASTERN
IL AND POSSIBLY OVER NORTHWEST INDIANA DEPENDING ON THE EXTENT OF
CLOUD COVER. HOWEVER, THIS AREA SAW MORE SIGNIFICANT RAINFALL
THURSDAY AND FUELS WILL LIKELY NOT HAVE HAD SUFFICIENT TIME TO DRY
BY SATURDAY, SO NO FIRE WEATHER WATCH IS PLANNED.
- IZZI
AVIATION
FOR THE 12Z TAFS...
WINDS WILL REMAIN NORTH THROUGH THE PERIOD, WITH A FAVORED DIRECTION
AROUND AROUND 010. WIND SPEEDS WILL CONTINUE TO INCREASE THROUGH MID-
MORNING AND GUST OVER 30 KNOTS AREA-WIDE THROUGH MUCH OF THE DAY.
WHILE GUSTS ARE EXPECTED TO REMAIN UNDER 35 KNOTS, THERE REMAINS A
POTENTIAL FOR GUSTS SURPASSING 35 KNOTS DURING THE AFTERNOON. THE
GUSTY WINDS WILL CONTINUE INTO THIS EVENING, BUT GRADUAL DECOUPLING
WILL SUPPORT A DECREASE IN SPEED. THIS SHOULD RESULT IN LLWS BY LATE
EVENING AS WIND SPEEDS REMAIN 40 KNOTS OR HIGHER AROUND 1 KFT.
OTHERWISE, MVFR CEILINGS WILL PERSIST EARLY THIS MORNING, BUT
WILL QUICKLY CLEAR FROM WEST TO EAST DURING THE MID-MORNING TO
EARLY AFTERNOON AS MUCH DRIER AIR ADVECTS INTO THE AREA.
KLUBER/KJB
MARINE
321 AM CDT
NORTHERLY GALES WILL PERSIST ACROSS THE SOUTHERN LAKE MICHIGAN
NEAR SHORES TODAY, BEFORE EASING A BIT TONIGHT. THE GRADIENT OVER
SOUTHERN LAKE MICHIGAN WILL REMAIN RATHER TIGHT ON SATURDAY AS
WELL, SO SOME BREEZY NORTHERLY WINDS AROUND 30 KT ARE LIKELY TO
PERSIST THROUGH SATURDAY BEFORE WINDS FINALLY DIMINISH SATURDAY
EVENING. WE ALSO CAN'T RULE OUT ANOTHER PERIOD OF GALE FORCE GUSTS
OVER SOUTHERN LAKE MICHIGAN ON SATURDAY. THE GALE WARNING
CURRENTLY RUNS THROUGH THIS EVENING. A SMALL CRAFT ADVISORY WILL
LIKELY BE ISSUED FOLLOWING THE GALE AND LASTING THROUGH SATURDAY
EVENING FOR STRONG WINDS AND HIGH WAVES.
KJB
LOT WATCHES/WARNINGS/ADVISORIES
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 1 AM SATURDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 1 AM SATURDAY.
LM...GALE WARNING...NEARSHORE WATERS UNTIL
10 PM FRIDAY.
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page