Issued by NWS Central Illinois
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 KILX 281444 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 944 AM CDT TUE OCT 28 2008 .DISCUSSION... ISSUED 945 AM CDT TUE OCT 28 2008 UPDATED THE FORECAST TODAY DUE TO THE EXPIRATION OF THE FREEZE WARNING AT 9 AM CDT. ALSO UPDATED TO HAVE A BIT MORE CLOUD COVER IN THE GRIDS...BUT STILL SHOULD BE A MOSTLY SUNNY DAY WITH FEW TO SCATTERED STRATOCU/CU CLOUDS APPEARING ALONG WITH SOME THIN CIRRUS CLOUDS SPREADING SSE ACROSS CENTRAL AND SE IL. 14Z/9 AM SURFACE MAP SHOWS 1037 MB LARGE HIGH PRESSURE OVER EASTERN KS/OK/TX AND RIDGING NORTHWARD INTO MN. STRONG 992 MB LOW PRESSURE WAS DEEPENING QUICKLY OVER WESTERN LONG ISLAND NEAR NYC. STILL HAVE A BIT OF A PRESSURE GRADIENT OVER CENTRAL IL WHICH WILL SUPPORT NW WINDS OF 10 TO 20 MPH AND STRONGEST OVER EAST CENTRAL IL. SUNNY SKIES OVER CENTRAL/SE IL SO FAR THIS MORNING WITH MOST OF THE LOW CLOUDS OVER LAKE MI INTO CENTRAL AND NE INDIANA. SOME CIRRUS AND FEW STRATOCU CLOUDS OVER NORTHERN IL. FIRST FREEZE ACROSS CENTRAL/SE IL EARLY THIS MORNING WITH LOWS IN THE 20S. TEMPS AT 930 AM HAVE RISEN ABOVE FREEZING INTO THE MID TO UPPER 30S. ALOFT A STRONG 534 DM 500 MB LOW WAS OVER DELAWARE AND EASTERN MD WITH A STRONG UPPER LEVEL TROF OVER EASTERN STATES. MEANWHILE 592 DM 500 MB HIGH WAS NEAR THE AZ/UT/NV BORDER. IL FIRMLY ENTRENCHED IN A NNW UPPER LEVEL FLOW. MODELS SIMILAR IN TAKING HIGH PRESSURE IN THE PLAINS INTO AR/LA/MS AND RIDGING NORTH INTO MO/IA THIS EVENING WHILE WEAKENING AT BIT TO 1032 MB. STRONG 992 MB LOW NEAR NYC DEEPENS TO 981 MB BY 06Z/1 AM AS IT LIFTS NORTHWARD TO NORTH OF NEW HAMSHIRE NEAR QUEBEC BY THE ST LAWRENCE SEAWAY. UPPER LEVEL TROF SHIFTS EAST TO THE EAST COAST. STRONG SURFACE AND UPPER LEVEL TROF WILL BE FAR ENOUGH EAST OF IL TO KEEP BROKEN LOW CLOUDS EAST OVER INDIANA TODAY. NAM CURULE SHOWS SCATTERED CUMULUS CLOUDS BY AFTERNOON OVER CENTRAL IL ESPECIALLY FROM HIGHWAY 51 EAST. THESE SCATTERED LOW CLOUDS DISSIPATE BY SUNSET/6 PM. 850 MB TEMPS STILL COOL TODAY WHICH ELEVATE TO MINUS 4C ALONG THE IL/IN BORDER BY SUNSET AND 0 TO 2C OVER WESTERN IL NEAR THE MS RIVER. HIGHS TO RANGE FROM 45 TO 50F WITH MILDEST READINGS AROUND 50F IN WESTERN IL WHERE MORE SUNSHINE AND HIGHER 850 MB TEMPS. HUETTL && .AVIATION... ISSUED 624 AM CDT TUE OCT 28 2008 HIGH PRESSURE OVER EASTERN KS WILL RESULT IN N/NWLY LOW LEVEL FLOW OVER IL THRU 00Z WED. THE SFC PRESSURE GRADIENT HAS RELAXED QUITE A BIT...SO WIND SPEEDS SHOULD BE MAINLY UNDER 15 KTS EXCEPT A LITTLE STRONGER AT BMI. ONLY CLOUDS WILL BE SCATTERED VFR CU OVER THE EASTERN HALF OF IL. AS THE SURFACE HIGH MOVES SOUTHWARD TO SOUTHERN AR TONIGHT...WINDS WILL BACK TO WLY AND DECREASE TO LESS THAN 10 KTS. 04 && .PREV DISCUSSION... ISSUED 200 AM CDT TUE OCT 28 2008 ANOTHER UNSEASONABLY COLD DAY IN STORE ACROSS CENTRAL ILLINOIS TODAY...BEFORE WARMER TEMPERATURES RETURN FOR THE END OF THE WEEK. 06Z SURFACE ANALYSIS SHOWS STRONG HIGH PRESSURE ANCHORED OVER THE CENTRAL CONUS...ALLOWING A COLD CANADIAN AIRMASS TO PENETRATE SOUTHWARD ALL THE WAY TO THE GULF COAST. ALOFT...RIDGING PREVAILS ALONG AND WEST OF THE ROCKIES...WHILE DEEP TROUGH IS IN PLACE EAST OF THE MISSISSIPPI RIVER. SHORT TERM...TODAY THROUGH THURSDAY UPPER TROUGH WILL SLOWLY BEGIN TO SHIFT FURTHER EASTWARD TODAY... ESULTING IN RISING HEIGHTS AND WARMING TEMPS ALOFT. FORECAST SOUNDINGS INDICATE VERY LITTLE MOISTURE IN THE PROFILE AND MUCH WEAKER LAPSE RATES THAN THOSE SEEN YESTERDAY. END RESULT WILL BE MOSTLY SUNNY SKIES...WITH ONLY FEW-SCT DIURNAL CU DEVELOPING. CU-RULE IS WEAKLY NEGATIVE ACROSS EAST-CENTRAL ILLINOIS...WITH MOST FAVORABLE LOCATION FOR CLOUD COVER FURTHER EAST/SOUTH BENEATH THE UPPER TROUGH. DESPITE LOTS OF SUNSHINE TODAY...TEMPS WILL ONLY BE A COUPLE OF DEGREES WARMER THAN YESTERDAY...MAINLY DUE TO THE MUCH COLDER START TO THE DAY AND A CONTINUATION OF N/NW LOW-LEVEL FLOW. WILL FOLLOW THE COOLER MET NUMBERS MOST CLOSELY...WITH AFTERNOON HIGHS ONLY REACHING THE MIDDLE TO UPPER 40S. SURFACE RIDGE APPROACHES FROM THE WEST TONIGHT...PRODUCING CLEAR SKIES AND DIMINISHING WINDS. HAVE UNDERCUT GUIDANCE BY A FEW DEGREES... ESULTING IN LOWS ONCE AGAIN DIPPING INTO THE 20S ACROSS THE BOARD. WARMING TREND WILL BEGIN ON WEDNESDAY...AS UPPER HEIGHTS CONTINUE TO RISE AND SURFACE FLOW BACKS TO W/SW. 850MB TEMPS JUMP INTO THE 3 TO 6C RANGE BY AFTERNOON...SUPPORTING HIGHS WELL INTO THE 50S. EVEN WARMER AIR ARRIVES ON THURSDAY...THANKS TO STRONG S/SW RETURN FLOW ON THE BACKSIDE OF THE DEPARTING HIGH. GIVEN ABUNDANT SUNSHINE AND DRY AIRMASS...WILL GO SEVERAL DEGREES ABOVE GUIDANCE...WITH HIGHS RISING INTO THE MIDDLE TO UPPER 60S. LONG TERM...FRIDAY THROUGH MONDAY GFS/ECMWF BOTH CONTINUE TO INDICATE NEXT FRONTAL BOUNDARY DROPPING THROUGH THE AREA DURING THE FRIDAY/SATURDAY TIME FRAME. 00Z OCT 28 GFS IS A BIT SLOWER WITH THE FRONT THAN ITS PREVIOUS RUNS...SO HAVE FOLLOWED THE MORE CONSISTENT ECMWF HERE. COLD FRONT WILL SINK SOUTHWARD OUT OF THE NORTHERN PLAINS AND PASS THROUGH CENTRAL ILLINOIS DURING THE DAY FRIDAY...BRINGING A FEW CLOUDS AND SLIGHTLY COOLER TEMPS IN THE LOWER 60S. AFTER THAT...ANOTHER COOL AND DRY AIRMASS WILL TAKE HOLD ACROSS THE MIDWEST THIS WEEKEND...WITH TEMPS NEAR OR SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
