355 AM CDT
ONLY SHORT TERM CONCERN IS POTENTIAL FOR SOME PATCHES/AREAS OF
FOG DEVELOPING ACROSS THE WESTERN COUNTIES OF THE FORECAST AREA
PREDAWN. WHILE DEW POINTS HAVE CONTINUED TO SLOWLY FALL OFF A
CLEAR SKY PREVAILS LIGHT WINDS ACROSS NW IL MAY BECOME CALM
BEFORE SUNRISE AS THE SURFACE RIDGE AXIS SLIDES E OVER SW WI...
NW IL AND EASTERN IA BY 12Z. A FEW LOCATIONS IN EASTERN IA AND
SW WI WHERE IT IS CALM ARE REPORTING SOME LIGHT FOG. DO NOT
ANTICIPATE WIDESPREAD FOG FORMATION SO WILL ONLY GO WITH PATCHY
EARLY MORNING FOG W OF A MSN-DKB-VYS LINE. OTHERWISE...WILL BE
SUNNY WITH SEASONABLE TEMPS TODAY WITH THE UPPER AND SURFACE
RIDGES BUILDING E ACROSS THE REGION.
NEXT CHANCE OF PRECIP COMES LATER SUN INTO MON AS THE UPPER TROF
CURRENTLY OVER THE PAC NW AND NORTHERN CA COASTS LIFTS FORM THE
UPPER MIDWEST TO WESTERN ONTARIO. THREAT OF MEASURABLE PRECIP
ONLY IN THE SLIGHT CHANCE TO LOW END CHANCE RANGE AS MAIN
FORCING WILL BE WELL NW AND N OF THE LOCAL AREA AND IT WILL STILL
BE UNDER THE INFLUENCE OF THE DRY LOW LEVEL AIR ASSOCIATED WITH
THE SURFACE RIDGE FORM NEW ENGLAND TO THE DEEP SOUTH SUN AND MON.
WITH THE RIDGE REMAINING IN PLACE AND A FAIRLY DEEP SURFACE LOW
LIFTING NE FROM THE NORTHERN PLAINS A STRONG S-SW LOW LEVEL FLOW
WILL DEVELOP ALONG WITH SIGNIFICANT WARM AIR ADVECTION. WHILE
CLOUDS ARE EXPECTED TO BE ON THE INCREASE SUN TEMPS SHOULD STILL
BE ABLE TO REACH THE LOWER 60S MOST LOCATIONS.
A MUCH GREATER THREAT OF RAIN COMES MON NIGHT THRU WED AS THE
SYSTEM CURRENTLY MOVING OVER THE GULF OF AK DIGS SE OVER THE
DESERT SW SUN NIGHT AND MON THEN CROSSES THE ROCKIES AND HIGH
PLAINS BY TUE MORNING BEFORE MOVING ENE TO THE MS VALLEY BY
MIDDAY WED. COMPARED TO THEIR PREVIOUS RUN THE MODELS ARE ALL
PRETTY MUCH IN AGREEMENT IN A SLOWER AND NOT AS DEEP UPPER LOW
MOVING OVER THE GREAT LAKES OR THE MIDWEST THU NIGHT AND FRI.
PROJECTIONS OF UPPER AND SURFACE SYSTEM TRACKS THAT FAR OUT IN
THE FUTURE ARE FREQUENTLY SUBJECT TO ADJUSTMENT AS IS THIS THE
CASE WITH THIS SYSTEM.
AT THIS POINT IN TIME IT LOOKS LIKE THE LOCAL FORECAST AREA WILL
STILL BE MILD MON AND AGAIN ACROSS THE SE PORTION OF THE AREA TUE
AS A WEAK FRONTAL BOUNDARY SLOWLY DROPS ACROSS NORTHERN IL LATE
MON BEFORE BECOMING STATIONARY ACROSS NORTHERN IN AND CENTRAL IL
MON NIGHT. THIS BOUNDARY WILL BE THE FOCUS FOR OVER-RUNNING RAIN
MON NIGHT...TUE...TUE NIGHT AS A SURFACE WAVE RIDES NE ALONG THE
QUASI-STATIONARY BOUNDARY AHEAD OF THE SECOND PLAINS UPPER SYSTEM.
MODEL SOLUTIONS DIVERGE SIGNIFICANTLY BY WED-THU THOUGH CURRENT
THERMAL PROFILES AND THICKNESS PROGS SUGGEST WE MAY SEE SOME
MIXED RAIN AND SNOW ON THE BACK END OF THIS SYSTEM AS IT WRAPS
COLD AIR S AND SE INTO IT AS IT MOVES E TO THE GREAT LAKES AND/OR
MIDWEST WED EVENING.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* GRADUAL EROSION OF NE WINDS.
* PERIOD OF LAKE STRATUS WITH CIGS ARND 3KFT AGL.
* PATCHY FOG...SHOULD REMAIN WEST OF ORD/MDW.
BEACHLER
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE CONTINUES TO SLIDE OVERHEAD AND STEADILY DIMINISH
WINDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN AND THE EASTERN
PERIPHERY OF THE SFC RIDGE...WINDS HAVE BECOME NORTHEASTLY. WITH
THE TEMPERATURE GRADIENT FROM THE AIR OVER LAKE MICHIGAN AND THE
WATER TEMPERATURE...THIS HAS ALLOWED A NARROW CHANNEL OF LAKE
STRATUS TO DEVELOP. FURTHER WEST WINDS HAVE DIMINISHED TO LESS
THAN 10KT AND WILL CONTINUE TO DIMINISH TO VRB03 OR VRB04 KT
OVERNIGHT. THE TEMP/DEW PT GRADIENT WILL CONTINUE TO
DIMINISH...AND COUPLED WITH RECENT RAINFALL SOME PATCHY FOG IS
EXPECTED TO DEVELOP AFT 10Z. FOR RFD/DPA AND AIRFIELDS WEST OF THE
URBAN HEAT ISLAND FOG WILL BEGIN TO DEVELOP. GUIDANCE HAS BACKED
OFF ON THE SIGNIFICANCE...HOWEVER IT STILL APPEARS POSSIBLE THAT
FOG WILL DEVELOP ARND 10Z AND COULD REDUCE VSBYS TO 1/2SM OR LESS
IN SOME LOCATIONS. HAVE INCLUDED THIS AS A TEMPO GROUP.
HIGH PRESSURE WILL THEN PROVIDE MINIMAL CLOUD COVER AND LGT
EASTERLY WINDS THIS AFTN THROUGH TONIGHT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* MEDIUM CONFIDENCE IN CIGS FORECAST THROUGH 10Z.
* HIGH CONFIDENCE IN CIGS FORECAST AFT 10Z.
* LOW CONFIDENCE IN FOG FORMATION.
* HIGH CONFIDENCE FOG WILL REMAIN WEST OF ORD/MDW.
* HIGH CONFIDENCE IN ALL OTHER ELEMENTS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR.
SUNDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.
MONDAY...SLIGHT CHANCE OF SHRA THEN CHANCE SHRA. CHANCE MVFR CIGS
LATE.
TUESDAY...SHRA LIKELY WITH CHANCE TSRA EARLY. CHANCE MVFR CIGS
EARLY.
WEDNESDAY...CHANCE OF SHRA...OTHERWISE VFR.
KREIN
&&
.MARINE...
225 PM CDT
AS THE LOW PRESSURE OVER SOUTHERN IL MIGRATES EAST...THE PRESSURE
GRADIENT WILL GRADUALLY RELAX OVER SOUTHERN LAKE MI TONIGHT. THIS
WILL ALLOW FOR NORTHEAST WINDS TO FALL SLOWLY AWAY FROM GALE
CRITERIA. WIND SPEED OBSERVATIONS NEAR THE SURFACE ARE ALSO
TRENDING DOWN...MANY JUST BELOW 30 KTS AS OF 215 PM. GUSTS
OF 25 TO 30 KTS WILL REMAIN POSSIBLE THROUGH THE EVENING HOURS.
WAVE HEIGHTS WILL ACCORDINGLY FALL TONIGHT...WITH THE HIGHEST
HEIGHTS SEEN BETWEEN THE SOUTH BUOY AND CHICAGO GIVEN THE LONG
DURATION NORTHEAST WIND DIRECTION. GIVEN THE HIGHER WINDS IN THE
IL AND IN NEAR SHORE AREAS...HAVE ISSUED A SMALL CRAFT ADVISORY TO
FOLLOW THE GALE WARNING. THIS WILL BE IN EFFECT INTO FRIDAY
MORNING WITH THE SLOWLY SUBSIDING WAVES. THE HIGH PRESSURE RIDGE
WILL MOVE OVER THE AREA QUICKLY DURING FRIDAY OFFERING A BRIEF
RESPITE...BEFORE SOUTHERLY FLOW AND A TIGHTENED PRESSURE GRADIENT
ONCE AGAIN BUILDS OVER LAKE MI. THIS LOOKS TO SUPPORT GALE
CONDITIONS...POTENTIALLY AS EARLY AS SATURDAY AFTERNOON...BUT MOST
FAVORED SATURDAY NIGHT INTO SUNDAY.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 AM FRIDAY.
&&
$$
