FXUS63 KARX 150813 AFDLSE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 310 AM CDT THU APR 15 2004 .SHORT TERM...TODAY THROUGH SATURDAY WARMTH AND WINDS CONTINUE TO BE THE MAIN FORECAST CONCERNS...WITH PCPN CHANCES CREEPING IN FOR THE WEEKEND. FIRE DANGER HIGH TODAY...SEE THE DISCUSSION BELOW FOR MORE INFORMATION. THE 500 MB RIDGE WILL CONTINUE TO BUILD ACROSS THE UPPER MISSISSIPPI RIVER VALLEY OVER THE NEXT FEW DAYS. A COUPLE SHORTWAVE TROUGHS WILL ATTEMPT TO MOVE THROUGH THE RIDGE...SPINNING FROM THE WEST COAST TO ACROSS THE NORTHERN PLAINS TONIGHT. THESE FEATURES WILL STAY NORTH OF THE FORECAST AREA THOUGH...AS THE UPPER LEVEL RIDGE HOLDS FAST. AT THE SFC...AN AREA OF LOW PRESSURE WILL DEVELOP IN RESPONSE TO THE UPPER LEVEL SHORTWAVES...TRACK INTO WESTERN MN BY THIS AFTERNOON...AND NORTHWEST TOWARD HUDSON/S BAY FOR FRI AFTERNOON. A TIGHT PRESSURE GRADIENT STILL LOOKS TO DEVELOP BETWEEN THIS INCOMING LOW...AND THE DEPARTING HIGH...LEADING TO A STRONG SOUTHERLY FLOW FOR THE FORECAST AREA. AS FOR THOSE WINDS...UNI-DIRECTIONAL FLOW FROM 850 MB TO THE SFC HAS THE POTENTIAL TO MIX THE 40 KT 850 WINDS TO THE SFC. BUFKIT MOMENTUM TRANSFER WOULD BRING 30-35 KTS DOWN IN RST. RH FIELDS AND FORECAST SOUNDINGS INDICATE SOME INCREASE IN UPPER LEVEL MOISTURE...PER THE CURRENT HIGH CLOUDS TO THE WEST...BUT DON/T FEEL THIS WILL LIMIT THE MIXING MUCH. IT SHOULD BE WINDY/BREEZY DAY AS A RESULT. DON/T FEEL THE WINDS IN THE OPEN...UNSHELTERED AREAS...WEST OF THE RIVER WILL BE ENOUGH FOR A WIND ADVISORY RIGHT NOW. IT BEARS WATCHING THOUGH. FOR TEMPS...UNDERESTIMATED THE EFFECT THE DRY CONDITIONS WOULD HAVE ON HIGH TEMPS...WITH MOST LOCATIONS REACHING 70 OR BETTER YESTERDAY. 850 MB TEMPS WILL CLIMB A COUPLE DEGREES OVER YESTERDAY TODAY...AND THEN A COUPLE MORE FOR FRIDAY. SOME HIGH CLOUDS WILL DRIFT ACROSS THE REGION...FILTERING OUT SOME SUN...BUT NOT ENOUGH TO INHIBIT THE WARMING...AND MIXING. MID TO UPPER 70S SHOULD BE THE RULE FOR MOST OF THE FORECAST AREA TODAY. THE WINDS TURN MORE TO THE SOUTHWEST ON FRIDAY...AND NOT AS STRONG. MORE CLOUDS TO DEAL WITH TOO. STILL...CONTINUED WARM AIR ADVECTION IN THE LOW LAYERS...AIDED BY THE DRY CONDITIONS AND CONTINUED MIXING...WILL LEAD TO ANOTHER WARM DAY ON FRI. CAN/T RULE OUT SOME AREAS IN THE SOUTH REACHING 80. RAIN? SOMETIME? ANYTIME? WILL IT HELP IF I SAY PLEASE? WITH THIS NEXT SYSTEM...PROBABLY NOT. THE BEST VORTICITY ADVECTION WILL BE WELL NORTH OF THE FORECAST AREA...ALONG WITH THE FAVORABLE QG CONVERGENCE. THERE IS SOME MINOR FRONTOGENETIC FORCING WITH THE SFC FRONT...WHICH LAYS UP ACROSS THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT. THAT WILL BECOME MORE OF A FACTOR THIS WEEKEND. THERE IS SOME 850 MOISTURE RETURN OUT AHEAD OF THIS BOUNDARY...MAINLY FOR THIS EVENING...ALTHOUGH THE NOSE OF THE LOW LEVEL JET PUNCHES WELL NORTH...THROUGH THE ARROWHEAD OF MN. ASIDE FROM THIS LOW LEVEL MOISTURE TRANSPORT...THE OTHER MOISTURE FIELDS ARE NOT VERY FAVORABLE. RH AND FORECAST SOUNDINGS ONLY INDICATE SOME HIGH/MID LEVEL SATURATION FOR LATE THIS AFTERNOON AND EVENING. CAN/T COMPLETELY RULE OUT PCPN FOR THE FORECAST AREA...BUT CHANCES LOOK SMALL...AND "BETTER" ACROSS NORTHERN SECTIONS. BACK TO THAT FRONTAL BOUNDARY. MODELS CLOSE ON THE APPROXIMATE LOCATIONS WHERE IT WILL LIE BY FRI NIGHT...ROUGHLY FROM NORTHEAST WI INTO CENTRAL IA. THE 850 MB LOW LEVEL JET/MOISTURE TRANSPORT IS EXPECTED TO NOSE INTO NORTHWEST ILL/SOUTHERN WI OVERNIGHT FRI. THE INTERACTION BETWEEN THIS AND THE SFC FEATURES SHOULD LEAD TO SOME PCPN ACROSS PARTS OF SOUTHERN WI...EASTERN IA AND NORTHERN ILL. THE PROSPECTS FOR MORE WIDESPREAD RAIN START TO IMPROVE ON THE WEEKEND. WITH THE 500 MB FLOW HAVING TURNED TO A MORE SOUTHWEST TRAJECTORY FOR THE REGION...THIS SFC BOUNDARY WILL HAVE LITTLE REASON TO MOVE ON THIS WEEKEND. SO...A SHORTWAVE MOVING FROM THE WEST COAST...INTO THE MN/IA BY SAT NIGHT WILL HAVE SOMETHING TO WORK WITH. FRONTOGENESIS WILL INCREASE ALONG THE BOUNDARY AS A RESULT...WITH A SFC LOW DEVELOPING IN THE VICINITY OF THE UPPER LEVEL FEATURE. THE LOW LEVEL JET AND BEST LOW LEVEL MOISTURE TRANSPORT WILL PUSH INTO AND NORTH OF THE SFC BOUNDARY...AND LIKELY FIRE AN MCS ACROSS WI FOR SAT NIGHT. BEFORE THAT THOUGH...CAPES OF 1000-2000 J/KG ARE CURRENTLY EXPECTED ACROSS NORTHEAST IA FOR SAT AFTERNOON...AND THIS...WITH THE VICINITY OF THE SFC FRONT AND OTHER LINGERING BOUNDARIES...COULD LEAD TO SOME AFTERNOON CONVECTION. A BREAK FROM THE DRY CONDITIONS LOOKS IN THE OFFING FOR AT LEAST PARTS OF THE FORECAST AREA. .LONG TERM...SUNDAY THROUGH WEDNESDAY SHOWER/STORM CHANCES WILL PERSIST ON SUNDAY...AS SFC BOUNDARIES AND INSTABILITY PERSIST. THEN...THE MORE ACTIVE...SOUTHWEST FLOW LOOKS TO CONTINUE FOR NEXT WEEK. CURRENT FORECAST LOOKS GOOD AND WON/T CHANGE MUCH. && .FIRE WEATHER... NOT MUCH CHANGE IN WHAT HAS BEEN EXPECTED FOR THE PAST COUPLE DAYS. SOUTH WINDS WILL CONTINUE TO INCREASE TODAY AS THE PRESSURE GRADIENT TIGHTENS. UNI-DIRECTIONAL WINDS AND MIXING FROM 850 MB TO THE SFC SHOULD BRING AT LEAST 30-35 KT WINDS DOWN AT TIMES...WEST OF THE MISSISSIPPI RIVER. TEMPERATURES WILL POP UP INTO THE MID TO UPPER 70S...BUT ONLY A 10 DEGREE INCREASE IN DEWPOINTS IS ANTICIPATED. THIS WILL KEEP MIN AFTERNOON HUMIDITIES IN THE LOWER 30 PERCENT RANGE. THERE IS THE POTENTIAL THAT EVEN DRIER AIR COULD BE MIXED DOWN TOO...DROPPING THE HUMIDITIES FURTHER. THIS IS CLOSE TO RED FLAG CRITERIA...BUT GIVEN THE DRY FUELS AND PRE-GREEN UP CONDITIONS OF THE VEGETATION...FEEL ITS CLOSE ENOUGH. WILL ISSUE A RED FLAG WARNING TO REPLACE THE FIRE WEATHER WATCH. THIS WILL INCLUDE SOUTHEAST MN...AND WESTERN/CENTRAL WI. COORDINATED WITH MKX...MPX...AND GRB...THANKS MUCH! && .ARX...WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...RED FLAG WARNING THIS AFTERNOON... MNZ079-086>088-094>096. WI...RED FLAG WARNING THIS AFTERNOON... WIZ017-029-032>034-041>044-053>055-061. && $$ RIECK