####018003646#### FXUS63 KEAX 152225 AFDEAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 425 PM CST SUN FEB 15 2009 .DISCUSSION... WATER VAPOR IMAGERY ACROSS THE NATION TODAY SHOWS A PROGRESSIVE ZONAL PATTERN IN CONTROL OF THE CONUS. FEATURES OF NOTE FOR THIS WEEKS FORECAST ARE...AMONG OTHERS...THE CUTOFF LOW SPINNING OFF THE COAST OF NORTHERN CALIFORNIA...THE SHORTWAVE FARTHER TO THE NORTHWEST OVER THE ALEUTIAN ISLANDS...AND ANOTHER SHORTWAVE NORTHWEST OF ALASKA. OTHERWISE...OF NOTE LOCALLY IS THE SNOW PACK VISIBLE ON SATELLITE IMAGERY TODAY ACROSS FAR NORTHERN MISSOURI. A SMALL SHORTWAVE...CURRENTLY ROUNDING THE EAST PACIFIC CUTOFF...WILL EJECT THROUGH THE INTER-MOUNTAIN WEST AND INTO THE CENTRAL PLAINS OVER THE NEXT TWO DAYS. THIS WAVE HAS LITTLE SIGNIFICANCE ON OUR FORECAST OTHER THAN IT WILL HELP POSITION THE CUTOFF LOW FOR THE ALEUTIAN ISLANDS SHORTWAVE SO THAT IT CAN KICK IT EAST THROUGH THE PLAINS IN THE TUESDAY TO WEDNESDAY TIME PERIODS. SO FOR MONDAY AND TUESDAY...AHEAD OF THE EJECTING AND SHEARING CUTOFF LOW...WINDS WILL PREVAIL FROM THE SOUTH...BRINGING SOME LIMITED MOISTURE NORTH FROM THE GULF ALONG WITH ABOVE NORMAL TEMPERATURES. TEMPERATURE WISE OVER THE NEXT TWO DAYS...HAVE GONE WITH THE WARMER GUIDANCE NUMBERS...THOUGH FOR TONIGHT I KEPT TEMPERATURES ON THE FRIGID SIDE ACROSS THE AREAS WHERE SNOW IS ON THE GROUND. TUESDAY WILL SEE THE SHEARING REMAINS OF THE CUTOFF LOW SWEEPING THROUGH THE PLAINS AS A SHORTWAVE DROPS OUT OF CENTRAL CANADA INTO THE NORTHERN PLAINS. THE SHEARING LOW AND SHORTWAVE FROM CANADA WILL WORK TOGETHER TO SPIN UP A SURFACE LOW IN THE CENTRAL PLAINS... BEFORE MOVING EAST AND DEVELOPING INTO A EAST CONUS TROUGH. WARM AIR ADVECTION AHEAD OF THE DEVELOPING SURFACE LOW...AND FRONTOGENIC FORCING TO THE NORTH OF THE WARM FRONT WITH THE CANADIAN SHORTWAVE...WHICH LOOKS TO BE IN THE VICINITY OF FAR NORTHERN MISSOURI TUESDAY...SHOULD PROVIDE LIKELY POPS ALONG THE IOWA BORDER WITH CHANCE POPS INTO CENTRAL MISSOURI FOR TUESDAY NIGHT INTO WEDNESDAY. HAVE CONTINUED TO GO WITH ONLY SLIGHT CHANCE POPS IN THE SOUTHWEST QUARTER OF THE FORECAST AREA AS EXPECTATIONS ARE THAT THE MOISTURE COMING NORTH WILL GET SHUNTED TO THE EAST A BIT. OTHERWISE...ADDED SOME ISOLATED THUNDERSTORM POPS TO THE SOUTHEAST THIRD OF THE FORECAST AREA FOR TUESDAY NIGHT/WEDNESDAY MORNING AS MID-LEVEL LAPSE RATES ARE PROGGED TO STEEPEN INTO THE 7 TO 8 C/KM RANGE. FOR THURSDAY...TEMPERATURES SHOULD STAY ON THE COOL SIDE IN THE WAKE OF THE COLD FRONT THAT WILL HAVE MOVED THROUGH THE DAY BEFORE. LOOKING INTO THE FAR END OF THE WORK WEEK...AND WEEKEND...THE SHORTWAVE NORTHWEST OF ALASKA WILL ZIP SOUTH INTO THE EASTERN CONUS TROUGH KEEPING THE IT LOADED THROUGH THE WEEKEND. TEMPERATURES ACROSS OUR AREA WILL BE A BATTLE BETWEEN THE WARM AIR TO OUR WEST AND COOL AIR TO OUR EAST AS A RESULT. HAVE OPTED TO KEEP THE FORECAST DRY IN THE EXTENDED FOR NOW...THOUGH THERE IS THE POTENTIAL FOR NEEDING TO ADD POPS INTO THE FRIDAY NIGHT/SATURDAY TIME FRAME AS THE SHORTWAVE NORTHWEST OF ALASKA SWINGS THROUGH THE PLAINS. HOWEVER...AT THIS TIME THOUGHTS ARE THAT MOISTURE WILL BE A LIMITING FACTOR. CUTTER && .AVIATION... VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. LIGHT NORTHEASTERLY SURFACE WINDS WILL GRADUALLY SHIFT TO THE SOUTHEAST BY TOMORROW MORNING...AS THE SURFACE HIGH MOVES EAST. NRR && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ ####018006648#### FXUS64 KEPZ 152229 AFDEPZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EL PASO TX/SANTA TERESA NM 329 PM MST SUN FEB 15 2009 .SYNOPSIS... A STRONG UPPER-LEVEL LOW OFF THE CALIFORNIA COAST WILL PUSH PLENTY OF HIGH LEVEL MOISTURE ACROSS THE AREA THROUGH MONDAY...RESULTING IN MOSTLY CLOUDY SKIES ACROSS MUCH OF THE BORDERLAND. THESE CLOUDS WILL PUSH SOUTH OF THE AREA MONDAY NIGHT. AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE AREA TUESDAY... RESULTING IN WINDY CONDITIONS ACROSS THE AREA TUESDAY AFTERNOON. QUIETER AND CONTINUED DRY WEATHER WILL PREVAIL WEDNESDAY THROUGH THE REMAINDER OF THE WEEK. && .DISCUSSION... BROAD UPPER LOW OFF THE NORTHERN CALIFORNIA COAST WILL BE THE MAIN FEATURE CONTROLLING THE WX ACROSS THE AREA OVER THE NEXT SEVERAL DAYS. SUBTROPICAL JET SOUTH OF THIS LOW HAS BEEN SENDING PLENTY OF THICK HIGH CLOUD COVER ACROSS MUCH OF THE DESERT SOUTHWEST THIS AFTERNOON. SATELLITE IMAGERY INDICATES THERE IS STILL PLENTY UPSTREAM AS WELL. WATER VAPOR CHANNEL REVEALS A SHORTWAVE EMBEDDED IN THE FLOW WEST OF BAJA AND DUE SOUTH OF THE UPPER LOW. 12Z GFS INITIALIZED THIS FEATURE PRETTY WELL...AND SEEMS TO HAVE A GOOD HANDLE ON WHERE THE UPPER LEVEL MOISTURE IS CURRENTLY. AS THIS WAVE TRANSLATES EAST OVERNIGHT... SOME MID-CLOUD COVER MAY ALSO MOVE IN ACROSS THE BORDERLAND BEFORE 12Z. WITH ALL THIS CLOUD COVER EXPECTED TO HANG AROUND THROUGH MORNING... I PULLED MIN TEMPS UP QUITE A BIT ACROSS THE FORECAST AREA...WITH MANY LOCATIONS STAYING ABOVE 40. EVEN THE HIGHER ELEVATIONS OF SACRAMENTOS...TEMPERATURES WILL STAY ON THE WARM SIDE GIVEN THE THERMAL BELT AND THE LACK OF RADIATIVE COOLING WHICH TYPICALLY COMPENSATES FOR THIS. HIGH CLOUDS WILL TEND TO THIN OUT AS THE WEAK INITIAL SHORTWAVE PASSES EAST OF THE AREA BY MIDDAY TOMORROW... BUT WILL THEN THICKEN UP AGAIN BY EVENING AS A 125-KT JET STREAM SETS UP OVER SOUTHERN CALIF/CENTRAL ALASKA...PLACING SOUTHERN NM IN THE RFQ. STRONGER SHORTWAVE WILL MOVE INTO WESTERN ARIZONA MONDAY NIGHT... BUT WILL QUICKLY WEAKEN AS IT TRANSLATES NORTHEAST AND BEGINS TO PHASE WITH AN ALBERTA CLIPPER DROPPING DOWN INTO THE NORTHERN GREAT PLAINS. LEE SFC CYCLOGENESIS WILL TAKE PLACE SOMEWHERE NEAR THE JUNCTIONS OF NM/TX/OK/CO... BUT THERE IS SOME QUESTION AS TO HOW STRONG THE SFC LOW WILL DEEPEN... WITH THE 18Z NAM WEAKER THAN THE 12Z GFS BY ABOUT 5 MB. AS A RESULT... THE NAM OFFERS UP A WEAKER PRESSURE GRADIENT ACROSS NEW MEXICO. HOWEVER... EVEN WITH THE WEAKER NAM...WINDS ACROSS THE AREA TUESDAY AFTERNOON WILL BE CLOSE TO ADVISORY CRITERIA...WITH 25-30 KT WINDS AT 800 MB. GFS SUGGESTS 35-40 KT AT THE SAME LEVEL...AND HAS CONTINUITY ON ITS SIDE... AND THE SUPPORT OF THE GEM GLOBAL GOING IN ITS FAVOR. NORMALLY NOT A BIG FAN OF 18Z RUNS EITHER...BUT FUTURE NAM RUNS WILL NEED TO BE WATCHED SINCE THE GFS VERTICAL COORD SCHEME IS NOT SUPPOSED TO BE VERY ACCURATE WITH LEE CYCLOGENESIS CASES TYPICALLY. ON THE OTHER HAND... THE NAM TENDS TO BE FLAKY AT THIS LONG OF A RANGE ESPECIALLY WITH SYSTEMS CURRENTLY WELL OFFSHORE. EITHER WAY...CORE OF STRONGEST WINDS ALOFT WILL BE WELL-TIMED WITH MAX HEATING...AND HIGH CLOUD COVER SHOULD PUSH SOUTH AND EAST OF THE AREA BY TUESDAY MORNING... MAYBE HANGING AROUND SE HUDSPETH COUNTY IF ANYWHERE. SO BOTTOM LINE...WINDY TUESDAY AFTERNOON... POSSIBLY ADVISORY LEVEL. GUSTS AROUND 50 MPH POSSIBLE ON EAST SLOPES. GFS STILL TRYING TO POP SOME QPF OVER THE GILA TUESDAY...BUT BELIEVE THIS IS HIGHLY OVERDONE. MOISTURE TOO FAR NORTHWEST OF THE AREA... SHORTWAVE TOO DEAMPLIFIED... AND UPPER FLOW HAS TOO STRONG OF A WESTERLY COMPONENT. KEPT A 10-POP IN FOR THE HIGHER ELEVATIONS OF THE GILA AS OUR SURROUNDING NEIGHBORS ARE STILL HANGING ON TO HIGHER POPS. BEYOND THAT...COOLER TEMPS WED...WITH A WEAK BACKDOOR FRONT SLIDING IN FROM THE NORTH WEDNESDAY NIGHT...BUT STAYING DRY. RIDGING BUILDS IN OVER THE WEST COAST THURSDAY AND FRIDAY... WARMING THINGS UP AGAIN. LONGWAVE TROUGH LOOKS TO CARVE OUT OVER THE GREAT LAKES LATE WEEK... KEEPING US IN A DRY NORTHWESTERLY FLOW... BUT VULNERABLE TO BACKDOOR FRONTAL PASSAGE AS UPPER LEVEL IMPULSES DROP INTO THE CENTRAL PLAINS. && .AVIATION...VALID 16/0000Z-17/0000Z... MDT TO STG TROUGH/CLOSED LOW OFF THE CALIF COAST BACKING WINDS ALOFT OVER THE SOUTHWEST UNITED STATES AND TAPPING MID/HI LEVEL CLOUDS. SYSTEM TO MOVE INTO NEW MEXICO STARTING LATE MONDAY/TUESDAY WITH A SLIGHT RISK OF SHOWERS FOR THE GILA WILDERNESS AND INCREASING STRONG GUSTY SOUTHWEST WINDS OVER THE BORDERLAND TUESDAY. VFR THROUGH THE PERIOD WITH MID HI CLOUDS SCT-BKN 10-15K FT AGL AND BKN-OVC 20-25K FT AGL. ONLY SCT HIGH CLDS ABV 20K FT MSL. SFC WINDS ENE-SSE 00Z-15Z THEN BECOMING SW 8-16 KTS AFT 15Z WITH OCNL HIGHER GUSTS ESPLY EAST FACING SLOPES. LGT/OCNL MDT TURBC OVR NR MTNS BLO 15K FT MSL. && .FIRE WEATHER... MDT TO STG TROUGH/CLOSED LOW OFF THE CALIF COAST BACKING WINDS ALOFT OVER THE SOUTHWEST UNITED STATES AND TAPPING MID/HI LEVEL CLOUDS. SYSTEM TO MOVE INTO NEW MEXICO STARTING LATE MONDAY/TUESDAY WITH A SLIGHT RISK OF SHOWERS FOR THE GILA WILDERNESS AND INCREASING STRONG GUSTY SOUTHWEST WINDS OVER THE BORDERLAND TUESDAY. FIRE DANGER IN THE MDT TO HIGH CATS. LIGHT EAST WINDS TONIGHT WITH FAIRLY GOOD OVERNIGHT RH RECOVERY. WINDS TO BECOME SW 8-16 MPH BY MONDAY AFTERNOON AHEAD OF ABOVE MENTIONED TROUGH WITH LOCAL HIGHER GUSTS EAST FACING SLOPES TO ADD TO WARMING AND DRYING. LOCAL DOWNSLOPE WINDS MONDAY NIGHT EAST SLOPES 10-20 MPH WITH WINDS BECOMING BY MIDDAY TUESDAY WSW 20-30 WITH GUSTS TO 40+ MPH...HIGHER EAST SLOPES AND PASSES. POTENTIAL LOCAL RED FLAG ISSUES SOME AREAS MONDAY AFT AND TUES BASICALLY LOWLANDS EAST OF THE RIO GRANDE. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 43 68 46 68 42 / 0 0 0 0 0 SIERRA BLANCA TX 42 66 46 67 36 / 0 0 0 0 0 LAS CRUCES 43 67 42 66 39 / 0 0 0 0 0 ALAMOGORDO 42 62 41 65 39 / 0 0 0 0 0 CLOUDCROFT 31 50 33 47 23 / 0 0 0 0 10 TRUTH OR CONSEQUENCES 34 64 37 64 37 / 0 0 0 10 0 SILVER CITY 33 59 35 54 29 / 0 0 0 10 10 DEMING 39 66 40 64 37 / 0 0 0 10 0 LORDSBURG 35 66 37 63 35 / 0 0 0 10 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 25-HARDIMAN / 20-NOVLAN