FXUS65 KBOU 301101 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 400 AM MST SAT DEC 30 2006 .SHORT TERM...UPPER LOW CONTINUES TO CRAWL EASTWARD. THE SHORTWAVE THAT SWUNG UNDER THE BOTTOM OF THE LOW OVERNIGHT HAS BECOME DOMINANT AND IS WOBBLING THE WHOLE CIRCULATION A BIT FURTHER NORTHWARD AS ANTICIPATED. HOWEVER...THE NORTHERN STREAM TROUGH IS LIMITING THE NORTHWARD MOTION OF THE CLOUD SHIELD...SHARPENING UP THE GRADIENT BETWEEN CLEAR SUBSIDENT AIR OVER WYOMING AND THE STORM TO OUR SOUTHEAST. PRESSURE GRADIENT IS ALSO STAYING MAINLY SOUTH OF US...WHICH HAS KEPT THE WINDS FROM COMING UP MUCH. MEANWHILE...THERE IS A STEADY STREAM OF LOW LEVEL DRY AIR FEEDING INTO THE SYSTEM FROM THE NORTH WHICH HAS ERODED THE NORTH EDGE OF THE LOW CLOUDINESS ACROSS NORTHERN COLORADO. SO...SOME SKEPTICISM ABOUT MUCH NORTHWARD MOTION OF THE SNOW...THOUGH THE SOUTHEASTERN FRINGE OF OUR AREA SHOULD SEE SOME ENHANCEMENT. SWING SHIFT ALREADY BACKED OFF ON WEATHER IN THE NORTHWEST PART...AND I WILL SHIFT THIS BOUNDARY A BIT FURTHER EAST SUGGESTING PROBABLY NO MORE SNOW IN DENVER. BLIZZARD WARNING STILL OK FROM LIMON THROUGH AKRON...BEST IN THE SOUTH BUT THERE WAS A FAIR AMOUNT OF SNOW YESTERDAY AND WINDS WILL BE MARGINAL. WILL COMPROMISE ON MODEL TRACKS OF THE SYSTEM...GIVING ANOTHER 2-5 INCHES OF SNOW TO THE BLIZZARD WARNING AREA. IF THE GFS IS CORRECT THE SNOW SHIELD WILL NOT MOVE NORTHWEST MUCH...AND THE ACCUMULATIONS WILL BE LIMITED TO THE EASTERN BORDER COUNTIES AND THE ARKANSAS VALLEY. ALONG THE FRONT RANGE...THE EDGE OF THE MID LEVEL CLOUD MAY HANG AROUND BUT LOW LEVEL DRYING CONTINUES AND WILL EVENTUALLY WIN. WILL DOWNGRADE BLIZZARD WARNING IN ZONE 41 TO A SNOW/BLOWING SNOW ADVISORY AND EVEN THIS WILL BE MARGINAL AS WINDS MAINLY IN THE EASTERN PART OF THE AREA. TAPERED SNOW FROM WEST TO EAST OVERNIGHT...IT MAY BE OVER BY SUNRISE SUNDAY. RAISED TEMPS IN AREAS WITH SOME CLEARING TODAY...AND LOWERED THEM TONIGHT FOR THE SAME REASON. .LONG TERM...ON SUNDAY NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA AS AN UPPER RIDGE MOVES IN. THE RIDGE AXIS MOVES IN LATE SUNDAY NIGHT AND ACROSS THE FORECAST AREA MONDAY. BY MONDAY AFTERNOON AND NIGHT SOUTHWESTERLY FLOW ALOFT IS PROGGED IN ADVANCE OF A WEAK UPPER TROUGH. THIS TROUGH MOVES ACROSS THROUGH THE DAY TUESDAY. THE GFS IS A BIT QUICKER THAN THE NAM. THERE IS A CLOSED CENTER AT THE BOTTOM OF THE TROUGH OVER SOUTHERN ARIZONA ON TUESDAY. IT MAKES ONE QUESTION THE TIMING OF IT ALL. DOWNWARD MOTION IS PROGGED ON THE QG VERTICAL VELOCITY FIELDS SUNDAY AND SUNDAY NIGHT. ON MONDAY AND MONDAY EVENING SOME WEAK UPWARD MOTION IS PROGGED IN ADVANCE OF THE NEXT OPEN TROUGH. BY LATER MONDAY NIGHT AND TUESDAY THE MOTION IS DOWNWARD AGAIN. THE LOW LEVEL GRADIENT IS STILL FAIRLY TIGHT OVER THE EAST ON SUNDAY...WITH DECENT NORTHWESTERLIES IN THE BOUNDARY LATER. BY SUNDAY NIGHT INTO TUESDAY A WEAK GRADIENT DOMINATED BY HIGH PRESSURE IS OVER THE FORECAST AREA. THERE COULD BE A TAD OF UPSLOPE WITH THE UPPER TROUGH MONDAY NIGHT INTO TUESDAY...BUT OF LITTLE CONSEQUENCE. MOISTURE-WISE... SUNDAY IS PRETTY DRY...SAVE FOR SOME LINGERING CLOUDINESS OVER THE EASTERN/SOUTHEASTERN BOARDER ZONES WITH THE EXITING STORM. SOME UPPER CLOUDINESS MOVES IN SUNDAY NIGHT...WAY MORE ON THE GFS. ON MONDAY THE GFS IS CLOUDY ALL AREAS FORM HIGH CLOUDS...THE NAM IS WAY DRIER. ON MONDAY NIGHT THE NAM GETS MORE IN THE LINE WITH THE UPPER LEVEL MOIST GFS. A BIT OF LINGERING POPS FOR THE BORDER ZONES EARLY SUNDAY...OTHERWISE NO POPS. FOR TEMPERATURES...SUNDAY IS 2-4 C WARMER THAN TODAY. MONDAY IS A BIT WARMER THAN SUNDAY. FOR THE LATER DAYS...STRONG NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THURSDAY...STRONG WESTERLY THURSDAY NIGHT INTO FRIDAY...THEN AN UPPER TROUGH TO MOVE OVER SATURDAY. THERE ARE SOME LIMITED ALPINE POPS GOING NOW...WILL LEAVE IT BE. && .BOU WATCHES/WARNINGS/ADVISORIES...BLIZZARD WARNING THROUGH 6 AM SUNDAY FOR THE FAR EASTERN PLAINS...ZONES 46>51. SNOW AND BLOWING SNOW ADVISORY THROUGH 6 PM TODAY EASTERN DOUGLAS AND WESTERN ELBERT COUNTIES...ZONE 41. && $$ GIMMESTAD/KOOPMEINERS
FXUS65 KBOU 301734 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 1030 AM MST SAT DEC 30 2006 UPDATE...IMPROVING CONDITIONS ACROSS THE NORTHEAST PLAINS HAS PROMPTED THE CANCELLATION OF THE BLIZZARD WARNING FOR ZONES 48>51 AS WELL AS THE SNOW AND BLOWING SNOW ADVSY FOR ZONE 41. IN ADDITION THE BLIZZARD WARNING THAT WAS IN EFFECT FOR EASTERN ELBERT AND LINCOLN COUNTIES (ZONES 46 AND 47) HAS BEEN DOWNGRADED TO A BLOWING SNOW ADVISORY. .SHORT TERM...UPPER LOW CONTINUES TO CRAWL EASTWARD. THE SHORTWAVE THAT SWUNG UNDER THE BOTTOM OF THE LOW OVERNIGHT HAS BECOME DOMINANT AND IS WOBBLING THE WHOLE CIRCULATION A BIT FURTHER NORTHWARD AS ANTICIPATED. HOWEVER...THE NORTHERN STREAM TROUGH IS LIMITING THE NORTHWARD MOTION OF THE CLOUD SHIELD...SHARPENING UP THE GRADIENT BETWEEN CLEAR SUBSIDENT AIR OVER WYOMING AND THE STORM TO OUR SOUTHEAST. PRESSURE GRADIENT IS ALSO STAYING MAINLY SOUTH OF US...WHICH HAS KEPT THE WINDS FROM COMING UP MUCH. MEANWHILE...THERE IS A STEADY STREAM OF LOW LEVEL DRY AIR FEEDING INTO THE SYSTEM FROM THE NORTH WHICH HAS ERODED THE NORTH EDGE OF THE LOW CLOUDINESS ACROSS NORTHERN COLORADO. SO...SOME SKEPTICISM ABOUT MUCH NORTHWARD MOTION OF THE SNOW...THOUGH THE SOUTHEASTERN FRINGE OF OUR AREA SHOULD SEE SOME ENHANCEMENT. SWING SHIFT ALREADY BACKED OFF ON WEATHER IN THE NORTHWEST PART...AND I WILL SHIFT THIS BOUNDARY A BIT FURTHER EAST SUGGESTING PROBABLY NO MORE SNOW IN DENVER. BLIZZARD WARNING STILL OK FROM LIMON THROUGH AKRON...BEST IN THE SOUTH BUT THERE WAS A FAIR AMOUNT OF SNOW YESTERDAY AND WINDS WILL BE MARGINAL. WILL COMPROMISE ON MODEL TRACKS OF THE SYSTEM...GIVING ANOTHER 2-5 INCHES OF SNOW TO THE BLIZZARD WARNING AREA. IF THE GFS IS CORRECT THE SNOW SHIELD WILL NOT MOVE NORTHWEST MUCH...AND THE ACCUMULATIONS WILL BE LIMITED TO THE EASTERN BORDER COUNTIES AND THE ARKANSAS VALLEY. ALONG THE FRONT RANGE...THE EDGE OF THE MID LEVEL CLOUD MAY HANG AROUND BUT LOW LEVEL DRYING CONTINUES AND WILL EVENTUALLY WIN. WILL DOWNGRADE BLIZZARD WARNING IN ZONE 41 TO A SNOW/BLOWING SNOW ADVISORY AND EVEN THIS WILL BE MARGINAL AS WINDS MAINLY IN THE EASTERN PART OF THE AREA. TAPERED SNOW FROM WEST TO EAST OVERNIGHT...IT MAY BE OVER BY SUNRISE SUNDAY. RAISED TEMPS IN AREAS WITH SOME CLEARING TODAY...AND LOWERED THEM TONIGHT FOR THE SAME REASON. .LONG TERM...ON SUNDAY NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA AS AN UPPER RIDGE MOVES IN. THE RIDGE AXIS MOVES IN LATE SUNDAY NIGHT AND ACROSS THE FORECAST AREA MONDAY. BY MONDAY AFTERNOON AND NIGHT SOUTHWESTERLY FLOW ALOFT IS PROGGED IN ADVANCE OF A WEAK UPPER TROUGH. THIS TROUGH MOVES ACROSS THROUGH THE DAY TUESDAY. THE GFS IS A BIT QUICKER THAN THE NAM. THERE IS A CLOSED CENTER AT THE BOTTOM OF THE TROUGH OVER SOUTHERN ARIZONA ON TUESDAY. IT MAKES ONE QUESTION THE TIMING OF IT ALL. DOWNWARD MOTION IS PROGGED ON THE QG VERTICAL VELOCITY FIELDS SUNDAY AND SUNDAY NIGHT. ON MONDAY AND MONDAY EVENING SOME WEAK UPWARD MOTION IS PROGGED IN ADVANCE OF THE NEXT OPEN TROUGH. BY LATER MONDAY NIGHT AND TUESDAY THE MOTION IS DOWNWARD AGAIN. THE LOW LEVEL GRADIENT IS STILL FAIRLY TIGHT OVER THE EAST ON SUNDAY...WITH DECENT NORTHWESTERLIES IN THE BOUNDARY LATER. BY SUNDAY NIGHT INTO TUESDAY A WEAK GRADIENT DOMINATED BY HIGH PRESSURE IS OVER THE FORECAST AREA. THERE COULD BE A TAD OF UPSLOPE WITH THE UPPER TROUGH MONDAY NIGHT INTO TUESDAY...BUT OF LITTLE CONSEQUENCE. MOISTURE-WISE... SUNDAY IS PRETTY DRY...SAVE FOR SOME LINGERING CLOUDINESS OVER THE EASTERN/SOUTHEASTERN BOARDER ZONES WITH THE EXITING STORM. SOME UPPER CLOUDINESS MOVES IN SUNDAY NIGHT...WAY MORE ON THE GFS. ON MONDAY THE GFS IS CLOUDY ALL AREAS FORM HIGH CLOUDS...THE NAM IS WAY DRIER. ON MONDAY NIGHT THE NAM GETS MORE IN THE LINE WITH THE UPPER LEVEL MOIST GFS. A BIT OF LINGERING POPS FOR THE BORDER ZONES EARLY SUNDAY...OTHERWISE NO POPS. FOR TEMPERATURES...SUNDAY IS 2-4 C WARMER THAN TODAY. MONDAY IS A BIT WARMER THAN SUNDAY. FOR THE LATER DAYS...STRONG NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THURSDAY...STRONG WESTERLY THURSDAY NIGHT INTO FRIDAY...THEN AN UPPER TROUGH TO MOVE OVER SATURDAY. THERE ARE SOME LIMITED ALPINE POPS GOING NOW...WILL LEAVE IT BE. && .BOU WATCHES/WARNINGS/ADVISORIES...BLOWING SNOW ADVISORY THROUGH 6 AM SUNDAY FOR EASTERN ELBERT AND LINCOLN COUNTIES..ZNS 46..47. && $$ COOPER/GIMMESTAD/KOOPMEINERS
FXUS65 KBOU 302107 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 200 PM MST SAT DEC 30 2006 .SHORT TERM...WILL FINISH BRUSHING THE REMAINING SNOW OFF THE FORECAST AS THE MAIN BAND OF SNOW ASSOCIATED WITH THE SLOW MOVING UPPER LOW WILL REMAIN WELL TO THE EAST AND SOUTH OF THE CWFA. THE SYSTEM OVER THE TX PANHANDLE IS PROGGED TO MOVE INTO NERN OK BY 12Z SUNDAY. AS A RESULT A DRIER NLY FLOW WILL CONTINUE TO ESTABLISH ITSELF OVER OUR AREA. WEAK UPWARD OMEGA CONTINUES TO DECRS OVERNIGHT WITH SUBSIDENCE DVLPG ON SUNDAY. ONLY CONCERN TNGT WILL BE THE THE PESKY FOG THAT HAS LINGERED OVER ERN LARIMER AND WELD COUNTIES THIS AFTN. WL LIKELY ADD SOME PATCHY COVERAGE IN THESE AREAS OVERNIGHT AS IT APPEARS TO BE GOING NO WHERE FAST. MSTR TRAPPED IN NORTH AND MIDDLE PARKS MAY ALSO ADD UP TO FOG OVRNGT... SO WILL ADDRESS IT THERE AS WELL. GUSTY WINDS AND SNOW CONTINUED OVER SRN LINCOLN COUNTY THIS AFTN. WAS CONTEMPLATING DROPPING THE BLOWING SNOW ADVISORY COMPLETELY BUT WILL KEEP IT GOING FOR SRN LINCOLN COUNTY. CONDITIONS SHUD IMPROVE LATER THIS EVENING. SWING SHIFT CAN DROP THE HIGHLIGHT ONCE THAT HAPPENS. ON SUNDAY...SHUD BE A FAIR AMOUNTS OF SUN OVER THE CWFA (ASIDE FM SOME HIGH LEVEL MSTR NEAR KANSAS) AS THE TROF CONTINUES ITS TRACK E AND AN UPPER RIDGE MOVES IN FM THE WEST. .LONG TERM...RIDGING ALOFT WILL BE MOVING ACROSS THE AREA SUNDAY NIGHT BEFORE MOVING OUT OVER THE PLAINS ON MONDAY. INCREASING CLOUDS ON MONDAY AHEAD OF THE NEXT SPLITTING TROF EXPECTED TO MOVE ACROSS THE REGION ON TUESDAY. THE BRUNT OF THE ENERGY IS EXPECTED TO DIVE INTO NRN BAJA...WHILE NRN BRANCH SENDS A WEAK RIPPLE ACROSS US ON MONDAY NIGHT AND TUESDAY. VERY LITTLE MSTR WITH IT SO WON'T EVEN MENTION ANY CHANCES OF PRECIP AT THIS TIME. GFS IS FURTHER SOUTH WITH THE SRN LOW BUT QUICKER WITH THE NRN BRANCH. EITHER WAY NO POPS FOR THE CWA. MODERATE RIDGING AGAIN THRU THE MIDDLE OF THE WEEK WITH A MODERATION IN TEMPS EXPECTED. SLOW WARM UP IN MOST LOCALES WITH EXTENSIVE SNOW COVER ON THE GROUND. THE NEXT OPEN WAVE WILL MOVE ACROSS COLORADO NEXT FRIDAY AND SATURDAY BEFORE AGAIN SPLITTING WITH THE SRN BRANCH BECOMING DOMINATE ACROSS THE DESERT SOUTHWEST. THIS SYSTEM IS SHOWING MORE MSTR BUT ONLY A QUICK SHOT OF UPLSOPE FLOW ACROSS NERN CO. NOT REALLY READY TO BUY OFF ON ANY OF THIS YET AND WILL LEAVE ERN CO DRY. BETTER CHANCES OF SNOW IN THE MTNS WITH BETTER OROGRAPHIC FLOW THERE. WILL KEEP ISOLATED POPS FOR NOW IN THE MTNS FOR FRI AND EARLY SAT. && .BOU WATCHES/WARNINGS/ADVISORIES...BLOWING SNOW ADVSY UNTIL 6 AM SUNDAY MORNING FOR SOUTHERN LINCOLN COUNTY...ZONE 47. && $$ COOPER/ENTREKIN
FXUS65 KBOU 311047 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 345 AM MST SUN DEC 31 2006 .SHORT TERM...QUIET DAY AS DEEP LOW MOVES EAST OF OUR AREA AND HIGH PRESSURE REPLACES IT. WINDS ALOFT AND SURFACE GRADIENT DECREASE THIS MORNING...STILL A LITTLE WIND BUT LIMITED BY DECENT SURFACE INVERSION AS SNOW KEEPS THE SURFACE AIR COLD. VERY DRY AIRMASS OFF THE SURFACE...00Z DENVER SOUNDING HAD 0.07 INCH OF PRECIPITABLE WATER. SOME OF THIS MIXED INTO THE SHALLOW BOUNDARY LAYER AT THE END OF THE DAY...AND A LITTLE CLOUD BAND HAS ALSO HELPED PREVENT FOG. CLOUDS WILL SHIFT EASTWARD THIS MORNING LEAVING SUNNY SKIES. NEXT BATCH OF HIGH CLOUDS OVER THE NORTHWEST WILL BRUSH NORTHERN COLORADO OVERNIGHT...PROBABLY KEEPING TEMPERATURES FROM GETTING COLDER THAN THIS MORNING DESPITE THE LIGHT WINDS. ONLY MINIMAL CHANGES TO THE FORECAST THIS MORNING. .LONG TERM...WEST-SOUTHWESTERLY FLOW ALOFT IS PROGGED FOR MONDAY. A WEAK UPPER TROUGH MOVES ACROSS MONDAY NIGHT INTO TUESDAY. TUESDAY AFTERNOON AND NIGHT HAS NORTH-NORTHEASTERLY FLOW ALOFT. THERE IS WEAK UPWARD MOTION PROGGED ON THE QG VERTICAL VELOCITY FIELDS MONDAY INTO MONDAY EVENING...THEN WEAK DOWNWARD MOTION THROUGH TUESDAY NIGHT. A PRETTY WEAK LOW LEVEL PRESSURE GRADIENT IS PROGGED FOR THE FORECAST AREA THROUGH TUESDAY. BY TUESDAY NIGHT INTO WEDNESDAY...LOW LEVEL TROUGHING EAST OF THE MOUNTAINS IS INDICATED. FOR MOISTURE...BOTH MODELS HAVE A PLENTY OF CLOUDS IN THE UPPER LEVEL MONDAY...CONTINUING SOMEWHAT MONDAY EVENING ON THE NAM ONLY. IT'S PRETTY DRY THE REST OF MONDAY NIGHT INTO EARLY WEDNESDAY. NO POPS. FOR TEMPERATURES...MONDAY IS 1-2.5 C WARMER THAN SUNDAY. TUESDAY IS MAYBE 0-1 C WARMER THAN MONDAY. FOR THE LATER DAYS...WEDNESDAY THROUGH SATURDAY...WILL CHANGE LITTLE. PERHAPS PUT IN SOME MINIMAL POPS IN THE MOUNTAINS WITH TIMING ISSUES OF THE END-OF-THE-WEAK TROUGH. ALSO WARMED WEDNESDAY'S HIGHS A TAD WITH THICKNESS GRIDS IN MIND. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ GIMMESTAD/KOOPMEINERS
FXUS65 KBOU 312109 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 210 PM MST SUN DEC 31 2006 .SHORT TERM...BENIGN PATTERN WILL PREVAIL THROUGH MONDAY. FOR TONIGHT THE UPPER LEVEL RIDGE WILL BE OVER ERN COLORADO. THE AMS WILL REMAIN DRY WITH THE EXCEPTION OF SOME HIGH LEVEL MSTR OVERRUNNING THE RIDGE LATE IN THE PERIOD. SUSPECT CONDITIONS OVER THE NORTHEAST PLAINS WILL DIE DOWN AS WELL AS BOUNDARY LYR WINDS DECOUPLE UNDER CLEAR SKIES. FLOW ALOFT WILL BECOME MORE WSWLY ON MONDAY AHEAD OF A STORM SYSTEM THAT WILL BE SPLITTING TO THE WEST AND NORTH AS IT APPROACHES THE STATE. ONLY CHANGE TO THE GRIDS ON MONDAY CONCERNED TEMPERATURES. MDLS MAINTAIN UPPER MSTR OVER COLORADO SO SKIES WILL BE PARTLY TO MOSTLY CLOUDY. THIS IN ADDITION TO MINIMAL SFC WINDS AND EXTENSIVE SNOW COVER SHUD LIMIT MAX TEMPERATURES. FOR THIS REASON I WILL KEEP MAX TEMPERATURES UNDER GUIDANCE...GENERALLY IN THE MID 30S ACRS THE URBAN CORRIDOR AND NORTHEAST PLAINS. .LONG TERM...FOR MONDAY NIGHT AND TUESDAY...NEXT UPPER LEVEL TROF WILL WEAKEN AND SPLIT ACROSS THE ROCKY MTN REGION. BULK OF THE ENERGY WILL DROP SOUTHWARD INTO BAJA WHILE NRN BRANCH SLIDES ACROSS NERN CO WITH LITTLE OR NO EFFECT. VERY LITTLE MOISTURE AND NO DYNAMICS SO NO POPS NEEDED FOR THIS INCOMING SYSTEM. BEYOND TUESDAY...FLOW ALOFT BECOMES MORE ZONAL AND WESTERLY AHEAD OF STRONG 150KT JET APPROACHING CO THU NITE AND FRI. ASSOCIATED STRONG COLD FRONT MOVES SOUTHWARD ALONG THE FRONT RANGE FRI AFTN WITH BRIEF BUT STORNG N-NE WINDS INTO FRI EVENING. FAIRLY DECENT MSTR AND STEEP LAPSE RATES FOR A TIME ALONG AND BEHIND THE FRONT. THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS SCENARIO FOR THE PAST FEW DAYS SO HAVE DECIDED TO ADD SOME LIGHT POPS ACROSS THE NERN PLAINS. HAVE ALSO BUMPED POPS UP TO SCATTERED FOR THE MTNS FOR FRI AND FRI NITE. DRIER AGAIN SAT AND SUNDAY AS HIGH PRESSURE BUILDS IN BEHIND THE TROF. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ COOPER/ENTREKIN