Forecast Discussions mentioning ACARS, received at FSL on 06/16/99

GENRLY HI PRES ACRS UPR MIDWEST RDG DOWN MS VLY. PCPN OVR IA HILITES RRQ/LFQ DIV AREA OF TWO HI LVL JETS RIDING DOWN EAST SIDE OF OMEGA BLOCK IN ROCKIES AND SWINGING UNDER UPR TROF FM ERN CAN TO UPR MDWST. DRY NELY WINDS UP TO 850 MB FCST TO REMAIN IN PLACE THRU PD OVR NRN IL INDICATING HI PRES TO INFLUENCE RGN WHILE UPR JET DRIFTS EWD OVRHD. ALREADY ON SATL AC/CI DRFTG EWD IN UPR FLO OVR WI/NWRN IL. CHC OF PCPN EDGING EWD BUT DRY NELY FLO TO ABSORB INCRSG RH AT PCPN ONSET WHICH IS LIKELY TO BE LT TNGT AND TWRD DAYBREAK. WUD PROBLY NOT PUT IN CHC TIL ERY WED WITH BEST CHC WED NGT INTO THU MRNG. UPR TROF SLIDES EWD INTO INDIANA ON THUR...ENDING THREAT OF PCPN BUT STILL RATHER CLDY.

NOW FOR TEMPS. MID 40S DIDNT CUT IT LAST NGT WITH SOME LINGERING CLDS AND HI SFC MSTR. WITH INCRSG CLDS TNGT IS NOT LIKELY TO GET THERE THIS TIME EITHER...UNLESS PCPN MAKES IT TO SFC WHERE LO DWPTS LET TEMPS DROP AS RH CLIMBS. ACARS/AND BALLOON SOUNDINGS SHOULD TEMPS FAIRLY ADIABATIC THRU 870 MB. EXPECT TEMPS TO EVEN MAKE LESS OF AN CLIMB UPWARD TMRW WITH CLD CVR AND SUB-850 AIR MASS STILL IN PLACE. SO HIGH TMRW NEAR 60. UPR AIR PCPN LIKELY TO SATURATE IT DOWN TO SFC BY TMRW NGT...SO CUD BE LOOKING AT SHOWERS (PROBLY NOT MORE THAN A TENTH IN MOST PLACES BY THUR AM FOR RIVER LEVEL INTERESTS). WLL STIL STICK WITH CHC TMRW NGT BUT BUMP UP THE POPS WED NGT AND THU. FOR CHI AREA HAD CU DVLPG WELL ESP OFF LK MI. SFC ANAL SHOWING HI PRES FORMED OVR LK MI ENHANCING ELY FLO AND SUBSIDENCE OUTWARD FM LK. THUS HAVE CLRG SPREADING SEWD FM LK MICH THIS AFTN. REST OF POPCORN CU SHUD DIMINISH WITH SUNSET. WHILE BKN CI SPREADS EWD OVR THE AREA. WITH LK TEMPS NEAR 60 WUD EXPECT MID 50S AGAIN FOR DOWNTOWN CHI EVEN WITH CLR SKIES TNGT.

EXTND SHOWING ANOTHER CHC ON SAT WITH SOME MODERATING TEMPS INTO 70S.

.CHI...FLW KISHWAUKEE AND FOX RIVERS.

BRUMER

AMS BEGINNING TO STABILIZE IN THE WAKE OF THE SHORTWAVE THAT WENT THROUGH THE AREA TUE EVENING. ACARS SOUNDINGS HAVE WEAK INVERSION BEGINNING TO DEVELOP AROUND 4000 FEET. PLENTY OF MOISTURE OVER THE AREA WITH SURFACE OBS INDICATING MULTIPLE CLOUD LAYERS UP TO 7000 FEET. IN ADDITION TO THE MOISTURE CROSS CASCADE GRADIENT...SEA-EAT ...STILL AT PLUS 7 MB ALTHOUGH IT IS SLOWLY DROPPING. NOTHING GOING ON TODAY TO SCOUR OUT THE MOISTURE WITH LIGHT ONSHORE PRES GRADIENTS CONTINUING AND WEAK SUBSIDENCE OVER THE AREA. MORE SUNSHINE ON THURSDAY AS UPPER LEVEL TROF BEGINS DIGGING ALONG 135W WHICH IN TURN WILL PUMP THE SHORTWAVE RIDGE TO THE EAST UP A LITTLE. THAT ALONG WITH A RELAXING OF THE ONSHORE GRADIENT AS THE PRESSURE BEGINS TO DROP OFFSHORE IN RESPONSE TO APPROACHING TROUGH WILL HELP REDUCE THE MARINE LAYER AND ADD A COUPLE OF DEGREES TO THE MAXS ON THURSDAY. .EXTENDED...EXTENDED MODELS IN PRETTY GOOD AGREEMENT FOR FRIDAY AND SATURDAY WITH NEGATIVELY TILTED TROUGH MOVING OVER WRN WA ON FRI AND SLOWLY MOVING EASTWARD ON SAT. NEW MRF LOOKING A LITTLE MORE LIKE THE EURO BUT STILL MUCH WEAKER WITH RIDGING OVER ERN PACIFIC FOR THE FIRST PART OF NEXT WEEK. EITHER WAY THE IMPROVING TREND LOOKS TO BEGIN ON SUNDAY. FELTON SEA 000 OLM 000 UIL 100

.KATX...VCP21/CSR21...OPERATIONAL .SEW...SCA CENTRAL AND E ENTRANCE OF THE STRAIT OF JUAN DE FUCA

LOCAL TOOL...SATELLITE IMAGERY AND 12Z UPPER AIR ANALYSIS SHOW A LONG WAVE RIDGE EXTENDING FROM WRN CANADA SWD THRU ID WHILE A LONG WAVE TROF IS EVIDENT ALONG 145W. THE NEGATIVELY TILTED SHORT WAVE TROF THAT BROUGHT THUNDERSTORM ACTIVITY TO NRN PORTIONS OF WA LATE YESTERDAY AFTN AND OVERNIGHT HAS NOW MOVED TO THE NE OUT OF OUR AREA. THIS LEAVES WA IN WEAK SW FLOW ALOFT WITH NOT MUCH GOING ON. 12Z SOUNDINGS FROM KUIL/KSLE AND MORNING ACARS SOUNDINGS OUT OF PAC NW AIRPORTS SHOW A RATHER STABLE BOUNDARY LAYER WITH ABUNDANT MOISTURE THRU ABOUT 9KFT CAPPED BY A STRONG/DRY MID LEVEL STABLE LAYER TO 15- 16KFT. DESPITE MORNING CLOUDS THE STRONG JUNE SUN SHOULD PROVIDE ENOUGH SURFACE HEATING TO PROVIDE A TEMPORARY LATE AFTN/EVENING BREAK TODAY. PREVIOUS SHORT TERM FORECASTS LOOK GOOD...WILL MAKE NO MORE THAN MINOR CHANGES TO PREVIOUS ZONE PACKAGE. .EXTENDED...12Z GUIDANCE SHOWS A STRONG LOOKING NEGATIVELY TILTED SHORT WAVE TROF ROTATING NE THRU THE AREA FRI FOR CLOUDS AND SCATTERED SHOWERS. EXTENDED MODELS APPEAR TO BE HAVING PROBLEMS SAT AND BEYOND IN DETERMINING WHETHER ENERGY WITH THIS SHORT WAVE TROF WILL MOVE EWD UNDER THE WRN CANADIAN BLOCK...AS PER MRF/UKMO AND TO SOME DEGREE ECMWF...OR WEAKEN AND MOVE OVER THE TOP OF THE BLOCK LEAVING WRN WA UNDER WEAK SW FLOW ALF PER CANADIAN MODEL. IN EITHER CASE THE STATE SEES IMPROVING CONDITIONS SUN AND BEYOND...THE ONLY QUESTION IS ON DEGREE OF WARMING. MAYBE THE 12Z AVN WILL PROVIDE SOME ANSWERS. WILL ADDRESS THIS AFTERNOON.

SEA 000 OLM 000 UIL 111 ALBRECHT

.KATX...VCP32/CSR32...OPERATIONAL .SEW...SCA CENTRAL AND E ENTRANCE OF THE STRAIT OF JUAN DE FUCA