255 PM CDT
AFD...CLIFFS NOTES VERSION OF SHORT-TERM...FULL DISCUSSION TO
FOLLOW SHORTLY. LONG-TERM DISCUSSION BELOW.
THE BIG NEWS FOR EVERYONE DEPRESSED BY THE WEATHER OVER THE LAST
WEEK OR SO IS WE ARE FINALLY GOING TO GET A BREAK AND A MUCH
DESERVED WARM-UP...BUT NOT UNTIL SUNDAY AND ESPECIALLY MONDAY.
MAIN CONCERNS WITH THIS FORECAST PACKAGE ARE EXTENT OF LAKE EFFECT
SHOWERS LATER THIS AFTERNOON AND TONIGHT...COLD TEMPERATURES AND
FROST IN OUTLYING AREAS TONIGHT...AND ANOTHER NIGHT OF COLD
TEMPERATURES ON SATURDAY NIGHT. THIS WILL BRING THE POTENTIAL FOR A
MORE WIDESPREAD FROST.
RC
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...FAIRLY QUIET WEATHER
IS IN STORE NEXT WEEK AS STRONG UPPER RIDGE SLOWLY WORKS EAST ACROSS
THE REGION. UNDER THE INFLUENCE OF THE UPPER HIGH...EXPECT TO SEE
PLENTY OF SUNSHINE AND ABOVE NORMAL TEMPERATURES AS H85 TEMPS WARM
INTO THE 13-16C RANGE...AND PERSIST THROUGH THE WEEK. AT THE
SURFACE...A GRADUAL WARMING TREND IS EXPECTED THROUGH THE
PERIOD...AS AFTERNOON HIGHS GO FROM LOW TO MID 70S TUESDAY...TO MID
AND UPPER 70S BY THURSDAY. BY FRIDAY...UPPER RIDGE IS EXPECTED TO
SLIDE EAST OF THE AREA AS LONGWAVE TROUGH BEGINS TO APPROACH FROM
THE WEST. AMONGST EXTENDED GUIDANCE AND GLOBAL ENSEMBLE
MEMBERS...THERE IS FAIRLY HIGH AGREEMENT LENDING TO HIGHER
CONFIDENCE IN FAIR/WARM WEATHER PERSISTING THROUGH THE END OF THE
WEEK. THE ECMWF IS MUCH SLOWER IN BRINGING THE UPPER TROUGH TOWARDS
THE END OF THE WEEK...BUT THIS SOLUTION WOULD ONLY KEEP THE NICE
WEATHER AROUND LONGER. BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 1920Z...
* NORTHWEST WINDS GUSTING TO 25-28 KT AT TIMES THIS AFTERNOON.
* SCATTERED -SHRA POSSIBLE LATE THIS AFTERNOON.
* SCT-BKN SKIES 3500-4500 FT.
* POTENTIAL FOR LAKE EFFECT SHRA LATER TONIGHT/SATURDAY MORNING.
* POTENTIAL FOR 2000-3000 FT LAKE EFFECT CIGS OVERNIGHT THROUGH
SATURDAY MORNING.
MDB
//DISCUSSION...UPDATED 1920Z...
WEAK UPPER WAVE AND STEEP LAPSE RATES HAVE RESULTED IN SCATTERED
SHOWER DEVELOPMENT ACROSS SOUTHERN WI WHICH ARE QUICKLY MOVING
SOUTHWARD. HAVE ADDED VCSH TO THE ORD/MDW/DPA TAFS FROM 21-00Z AND
IT IS POSSIBLE THAT THESE MAY IMPACT THE TERMINALS FOR BRIEF
PERIODS AND BRING ENOUGH RAIN TO AT LEAST WET THE RUNWAYS.
ACTIVITY WILL DIMINISH WITH SUNSET.
FROM 18Z...
NORTH TO NORTH-NORTHWEST WINDS CONTINUE EARLY THIS AFTERNOON AND
EXPECT THAT GUSTS WILL INCREASE TO AROUND 25 KT OR SLIGHTLY
HIGHER...WITH GUSTS OF 25-30 KT CONTINUING AT GYY. SCT-BKN LOWER
END VFR SKIES WILL CONTINUE THROUGH THE AFTERNOON WITH SKIES WELL
INLAND OF THE LAKE SEEING CLEARING AS THE SUN SETS. AREAS NEAR THE
LAKE AND ACROSS MUCH OF NORTHWEST INDIANA WILL SEE AT LEAST
SCATTERED SKIES CONTINUE THIS EVENING...WITH BROKEN SKIES PROBABLY
PREVAILING AT GYY THANKS TO THE LAKE. LAKE EFFECT SHOWERS WILL
BECOME MORE LIKELY INTO THE EVENING AND ESPECIALLY TONIGHT WITH
CURRENT RADAR MOSAIC SHOWING SOME DEVELOPMENT TRYING TO ORGANIZE
DOWN THE LONG AXIS OF THE LAKE. INITIAL ACTIVITY SHOULD STAY JUST
EAST OF GYY BUT WILL LIKELY DRIFT WESTWARD WITH TIME. MAY BE A
LITTLE SLOW ON THE VCSH MENTION THERE BUT ITS NOT COMPLETELY CLEAR
HOW QUICKLY THE BANDS WILL INTO THE EVENING. CONFIDENCE IS BETTER
IN LAKE EFFECT SHRA EVOLUTION INTO TONIGHT. LOW LEVEL FLOW WILL
BECOME SLIGHTLY EAST OF NORTH WITH CONVERGENCE SETTING UP ON THE
WESTERN SHORE OF THE LAKE. THIS WOULD SUPPORT A WESTWARD MOVEMENT
TO ANY ACTIVITY THIS EVENING AND OVERNIGHT. THIS WILL BRING AT
LEAST THE CHANCE FOR SHRA TO THE ILLINOIS SHORELINE OVERNIGHT INTO
SATURDAY MORNING WITH ACTIVITY POSSIBLY MOVING AS FAR INLAND AS
ORD/MDW. STILL SOME QUESTION IF DEVELOPMENT WILL CONTINUE
OVERNIGHT WITH PARAMETERS WANING A BIT BUT WILL STICK WITH VCSH
MENTION AT ORD/MDW. MVFR CIGS ARE ALSO POSSIBLE THERE...AS WELL AS
DPA. SHRA ACTIVITY SHOULD SHUTOFF BY EARLY AFTERNOON ALLOWING
SCATTERING OF SKIES. FURTHER INLAND...INCLUDING RFD...SKIES WILL
PROBABLY BE MOSTLY CLEAR WITH SOME STRATOCU POSSIBLY DEVELOPING
LATE MORNING. WINDS WILL BE LIGHTER WITH SOME GUSTS TO NEAR 20 KT
POSSIBLE DURING THE AFTERNOON.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 1920Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM-HIGH CONFIDENCE THAT -SHRA WILL MOVE INTO THE AREA
21-22Z...MAY DIRECTLY AFFECT TERMINALS FOR BRIEF PERIODS...BUT
ACTIVITY IS WIDELY SCATTERED.
* HIGH CONFIDENCE IN CEILING FORECAST THIS AFTERNOON.
* MEDIUM CONFIDENCE IN LAKE EFFECT SHRA AT LEAST BEING IN THE
VICINITY OF THE AIRPORT LATE TONIGHT AND SATURDAY MORNING.
* MEDIUM-HIGH CONFIDENCE IN LAKE EFFECT CEILINGS LATE TONIGHT AND
SATURDAY MORNING BUT LOW CONFIDENCE IN THEM BEING BELOW 3000 FT.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH THURSDAY...VFR.
MDB
&&
.MARINE...
143 PM CDT
MARINE FORECAST CONCERNS ARE FOCUSED ON GRADUAL DECREASE IN STRONG
NORTHERLY WINDS ACROSS LAKE MICHIGAN...HIGH WAVES AND ASSOCIATED
STORM/GALE/SMALL CRAFT ADVISORY HEADLINE ISSUES INTO SUNDAY.
LOW PRESSURE CONTINUES TO FILL NEAR TORONTO ONTARIO EARLY THIS
AFTERNOON. THIS LOW WILL CONTINUE TO WEAKEN AS IT DRIFTS EAST ACROSS
UPSTATE NEW YORK THIS EVENING...AND EVENTUALLY REFORMS OFF THE EAST
COAST. AS THIS OCCURS...HIGH PRESSURE OVER WESTERN ONTARIO AND THE
UPPER MIDWEST WILL SLOWLY DRIFT SOUTHEAST ACROSS THE NORTHERN AND
WESTERN GREAT LAKES AND THE MID MISSISSIPPI VALLEY THROUGH SUNDAY
MORNING. THIS WILL ALLOW CONTINUED GRADUAL WEAKENING OF THE SURFACE
PRESSURE GRADIENT ACROSS LAKE MICHIGAN.
AFTER THIS MORNINGS GUSTS IN EXCESS OF 50 KTS...AND WAVES HIGHER
THAN 20 FT PER BUOY AND SHIP OBS...WINDS HAVE SETTLED TO 35-40 KTS
FOR THE MOST PART ACROSS THE OPEN WATERS AND THE SOUTH SHORE WITH
WAVES NOW IN THE 12-15 FOOT RANGE PER LATEST BUOY OBS. THUS HAVE
ALLOWED THE STORM WARNING TO EXPIRE AS OF 1 PM CDT...REPLACED BY A
GALE WARNING WHICH WILL RUN THROUGH 1 AM CDT SATURDAY BASED ON
CONSISTENT MODEL GUIDANCE. WITH EXPIRATION OF GALE WARNINGS
TONIGHT...WILL HAVE TO HOIST SMALL CRAFT ADVISORIES FOR THE ILLINOIS
AND INDIANA NEARSHORE WATERS. LONG NORTHERLY FETCH AND CONTINUED
RATHER GRADUAL DECLINE IN WIND SPEEDS WILL HELP TO MAINTAIN WAVES
WELL ABOVE 4 FT PARTICULARLY ALONG THE INDIANA SHORE INTO SUNDAY
MORNING. WILL LIKELY BE ABLE TO KEEP ILLINOIS SHORE SMALL CRAFT
ADVISORIES A LITTLE SHORTER...WITH A SLIGHTLY MORE FAVORABLE FETCH
FOR ALLOWING WAVES TO SUBSIDE.
WINDS AND WAVES SHOULD BE MUCH LOWER FROM SUNDAY INTO THE MIDDLE OF
NEXT WEEK...AS BLOCKING PATTERN ALOFT ALLOWS HIGH PRESSURE RIDGE TO
LINGER ACROSS THE CENTRAL PART OF THE NATION AND THE WESTERN LAKES.
IN FACT WIND DIRECTION FORECAST BECOMES A BIT UNCERTAIN DUE TO VERY
WEAK GRADIENT DURING THIS PERIOD.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...LAKESHORE FLOOD WARNING...INZ002 UNTIL 4 PM FRIDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 1 AM
SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP TO WILMETTE HARBORS UNTIL 1 AM SUNDAY.
GALE WARNING...LMZ741-LMZ742-LMZ743 UNTIL 10 PM FRIDAY.
&&
$$
