FXUS65 KBOU 291054
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
355 AM MST FRI DEC 29 2006
.SHORT TERM...MODELS OBVIOUSLY HURTING WITH THE DETAILS OF WHAT IS
HAPPENING NOW. HUGE PLUME OF MOISTURE STREAMING NORTH OUT OF MEXICO
ACROSS WEST TEXAS AND WRAPPING BACK WESTWARD...WILL BE ARRIVING IN
DENVER SOON. MODELS NEVER BRING THIS WESTWARD...KEEPING THE
SIGNIFICANT PRECIPITATION ALONG THE EASTERN FRINGE OF OUR AREA. THIS
APPEARS TO BE TIED TO THE STRUCTURE OF THE TROUGH AND UNDERDOING THE
VORT MAX ON THE NORTH SIDE AND THE AMOUNT OF FLOW CURVING BACK
WESTWARD. NAM IS DOING BETTER HERE AS YOU MIGHT EXPECT BUT STILL NOT
VERY GOOD. IT PRODUCES ABOUT 3 INCHES OF SNOWFALL ON THE PALMER
DIVIDE THIS MORNING...THEN SHIFTS EVERYTHING EAST. GFS IS NEARLY DRY
THROUGHOUT. IN REALITY...THE NORTHERN PART OF THE LOW IS SHIFTING
WESTWARD A BIT WITH THE DRY SLOT OVER NEW MEXICO TRANSLATING
NORTHWESTWARD. SOUTHERN PIECE ROTATING AROUND THE BOTTOM JUST INTO
MEXICO. THIS WILL SWING AROUND THE EAST SIDE AND BECOME
DOMINANT...BUT WITH THE WHOLE CIRCULATION STATIONARY OR PERHAPS
SLIPPING WESTWARD A BIT...THIS WILL PROBABLY BE A BIT FURTHER WEST
THAN WHAT THE MODELS ARE SHOWING. THE EFFECT OF THIS LOOKS TO BE THE
MOISTURE BAND PIVOTING ON TOP OF US TONIGHT. I WOULD LIKE TO HAVE A
MODEL RUN THAT SHOWS THIS WELL...BUT IT DOES NOT EXIST. FLOW SHOULD
BE LIGHTER BUT STILL SOME EASTERLY FLOW WITH LOW LEVEL GRADIENT
STEADY OR PICKING UP GRADUALLY. SO AT LEAST LIGHT SNOW LIKELY TO
CONTINUE THROUGH MY PERIOD. ONE OTHER NOTE...THE SURFACE WINDS ARE
ALREADY ABOUT 10 KT MORE THAN THE MODELS SHOW...HOPEFULLY THAT TREND
WILL NOT CONTINUE.
SO...I WILL HIT THE MORNING HARD AS THIS PART SEEMS
STRAIGHTFORWARD...THEN KEEP LIGHT SNOW GOING...PERHAPS MODERATE
THROUGH TONIGHT. THOUGHT ABOUT A BLIZZARD WARNING EVERYWHERE AS
WINDS WILL BE CLOSE MOST PLACES...BUT FOR NOW JUST ISSUING THAT
WHERE CONFIDENCE IS HIGHEST ALONG OUR EASTERN TIER. WITH LESS
CERTAINTY FURTHER WEST...WILL OPT TO EXTEND THE WINTER STORM
WARNING. HARD TO TELL HOW MUCH THE SNOW WILL TAPER OFF OR WHEN...AND
WINDS LIKELY NEAR BLIZZARD CRITERIA WITH LIGHT SNOW ANYWAY...SO I
WILL RUN THE WARNING THROUGH TONIGHT AND WE CAN ADJUST THAT IF THE
ANSWER BECOMES EVIDENT. IN SOUTH PARK SNOW CONTINUES BUT EVENTUALLY
NE FLOW SHOULD SHUT IT OFF...WILL RUN THE WARNING THROUGH TODAY.
.LONG TERM...GREAT MAJORITY OF MODELS HAVE THE UPPER FEATURE
CENTERED OVER THE SOUTHERN TEXAS PANHANDLE ON SATURDAY AT 12Z. THE
NAM IS A BIT FURTHER NORTH BUT AGAIN ALL OF THEM ARE QUITE CLOSE.
BY SUNDAY 12Z THEY ALL HAVE IT OVER NORTHERN OKLAHOMA WITH THE UKMET
THE FURTHEST WEST OF THE BATCH. BY MONDAY MORNING 12Z A SHORT WAVE
RIDGE ALOFT IS OVER US WITH A TROUGH/CLOSED LOW OVER THE SOUTHERN
GREAT BASIN. THE QG VERTICAL VELOCITY FIELDS HAVE DECENT UPWARD
MOTION PROGGED OVER THE FORECAST AREA SATURDAY AND SATURDAY
EVENING. SOME LINGERS OVER THE NORTHEAST CORNER INTO SUNDAY MORNING
AS THE UPPER FEATURE PULLS AWAY. MOISTURE-WISE...THE NAM HAS PLENTY
SATURDAY THROUGH SUNDAY EVENING FOR THE PLAINS AND FOOTHILLS. THE
MOUNTAINS BEGIN DRYING OUT BY SUNDAY AFTERNOON. IN STARK CONTRAST
...THE GFS STARTS DRYING OUT THE WESTERN THREE-QUARTERS OF THE
FORECAST AREA BY SATURDAY MORNING. THE FAR EASTERN BORDER STAYS
MOIST. OVERNIGHT SATURDAY INTO SUNDAY...IT SHOWS VIRTUALLY NO
CLOUDINESS AT ALL FOR THE FORECAST AREA. VERY DRY SUNDAY TOO. IT'S
STRANGE THAT THE LOCATION OF ALL THE MAIN FEATURES OF THIS STORM ARE
NEARLY IDENTICAL BETWEEN THE NAM AND GFS...YET THE GFS' MOISTURE
GOES MISSING SOMETHING FIERCE. PERHAPS IT HAS SOMETHING TO DO WITH
SHRINKING PIECE OF ENERGY TO THE NORTH. THAT NORTHERN PIECE IS MORE
SIGNIFICANT ON THE GFS THROUGH SATURDAY NIGHT...WHICH MAY HELP CAUSE
THE MORE SIGNIFICANT DOWNSLOPING BY SATURDAY NIGHT. ANYWAY IT DOES
NOT SEEM TO MATTER ALL THAT MUCH AS THE GFS IS HAVING TROUBLE RIGHT
NOW WITH CURRENT MOISTURE/QPF. NEED TO LEAN WAY MORE TOWARDS THE
NAM WITH THIS MOISTURE ISSUE.
CONCERNING THE HIGHLIGHTS...THE DEEP UPSLOPE CIRCULATION GOES AWAY
DURING THE DAY SUNDAY. THE LOW LEVEL PRESSURE GRADIENT POINTS TO
BLIZZARD CONDITIONS FOR ABOUT THE EASTERN HALF OF THE PLAINS
SATURDAY...SATURDAY NIGHT...INTO SUNDAY. THE PLAINS CLOSER TO THE
FOOTHILLS AND THE FOOTHILLS THEMSELVES GET DOWNSLOPY EVEN ON THE NAM
BY SUNDAY. THE QPF FIELDS ARE ALSO PROBLEMATIC...WITH THE GFS
SHOWING BARELY ANY FOR THE FORECAST AREA...AND THE NAM PRETTY SPARSE
BY SATURDAY EVENING. AND AGAIN...ARE ANY OF THESE MODELS TIMING
THIS CLOSED SYSTEM ACCURATELY? A BLIZZARD WARNING FOR SOME OF THE
EASTERN PLAINS ZONES IS A GOOD BET INTO SUNDAY AFTERNOON ANYWAY.
WILL GO OVER IT WITH THE SHORT TERM MAN. IT WILL SNOW OVER THE REST
OF THE PLAINS SATURDAY INTO SUNDAY BUT WITH TOO MUCH UNCERTAINTY
ABOUT INTENSITY AND AMOUNTS...WILL...UNFORTUNATELY...HAVE TO KEEP A
WATCH GOING. WILL KEEP THE WATCH FOR THE FOOTHILLS AND MOUNTAINS
THROUGH SUNDAY DAWN. FOR TEMPERATURES...WILL LEAN MORE TOWARDS THE
NAM...A BIT COOLER. NO CHANGE FOR THE LATER DAYS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING THROUGH
TONIGHT FOR THE FRONT RANGE MOUNTAINS...FOOTHILLS...AND
ADJACENT PLAINS...ZONES 33>36..38>45.
WINTER STORM WARNING THROUGH TODAY FOR SOUTH PARK...ZONE 37.
BLIZZARD WARNING NOW THROUGH SUNDAY FOR ZONES 46>51.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY DAWN FOR ZONES 33>36.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY FOR ZONES 38>45.
&&
$$
GIMMESTAD/RJKOOPMEINERS
FXUS65 KBOU 291846
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
1145 AM MST FRI DEC 29 2006
OPTED TO DOWNGRADE THE HIGHLIGHTS IN ZONES 33>39 TO SNOW AND BLOWING
SNOW ADVISORIES THROUGH TONIGHT AS THE LATEST MDLS KEEP THE HEAVIEST
SNOW EAST AND SOUTH OF DENVER THROUGH THAT TIME FRAME.
.SHORT TERM...MODELS OBVIOUSLY HURTING WITH THE DETAILS OF WHAT IS
HAPPENING NOW. HUGE PLUME OF MOISTURE STREAMING NORTH OUT OF MEXICO
ACROSS WEST TEXAS AND WRAPPING BACK WESTWARD...WILL BE ARRIVING IN
DENVER SOON. MODELS NEVER BRING THIS WESTWARD...KEEPING THE
SIGNIFICANT PRECIPITATION ALONG THE EASTERN FRINGE OF OUR AREA. THIS
APPEARS TO BE TIED TO THE STRUCTURE OF THE TROUGH AND UNDERDOING THE
VORT MAX ON THE NORTH SIDE AND THE AMOUNT OF FLOW CURVING BACK
WESTWARD. NAM IS DOING BETTER HERE AS YOU MIGHT EXPECT BUT STILL NOT
VERY GOOD. IT PRODUCES ABOUT 3 INCHES OF SNOWFALL ON THE PALMER
DIVIDE THIS MORNING...THEN SHIFTS EVERYTHING EAST. GFS IS NEARLY DRY
THROUGHOUT. IN REALITY...THE NORTHERN PART OF THE LOW IS SHIFTING
WESTWARD A BIT WITH THE DRY SLOT OVER NEW MEXICO TRANSLATING
NORTHWESTWARD. SOUTHERN PIECE ROTATING AROUND THE BOTTOM JUST INTO
MEXICO. THIS WILL SWING AROUND THE EAST SIDE AND BECOME
DOMINANT...BUT WITH THE WHOLE CIRCULATION STATIONARY OR PERHAPS
SLIPPING WESTWARD A BIT...THIS WILL PROBABLY BE A BIT FURTHER WEST
THAN WHAT THE MODELS ARE SHOWING. THE EFFECT OF THIS LOOKS TO BE THE
MOISTURE BAND PIVOTING ON TOP OF US TONIGHT. I WOULD LIKE TO HAVE A
MODEL RUN THAT SHOWS THIS WELL...BUT IT DOES NOT EXIST. FLOW SHOULD
BE LIGHTER BUT STILL SOME EASTERLY FLOW WITH LOW LEVEL GRADIENT
STEADY OR PICKING UP GRADUALLY. SO AT LEAST LIGHT SNOW LIKELY TO
CONTINUE THROUGH MY PERIOD. ONE OTHER NOTE...THE SURFACE WINDS ARE
ALREADY ABOUT 10 KT MORE THAN THE MODELS SHOW...HOPEFULLY THAT TREND
WILL NOT CONTINUE.
SO...I WILL HIT THE MORNING HARD AS THIS PART SEEMS
STRAIGHTFORWARD...THEN KEEP LIGHT SNOW GOING...PERHAPS MODERATE
THROUGH TONIGHT. THOUGHT ABOUT A BLIZZARD WARNING EVERYWHERE AS
WINDS WILL BE CLOSE MOST PLACES...BUT FOR NOW JUST ISSUING THAT
WHERE CONFIDENCE IS HIGHEST ALONG OUR EASTERN TIER. WITH LESS
CERTAINTY FURTHER WEST...WILL OPT TO EXTEND THE WINTER STORM
WARNING. HARD TO TELL HOW MUCH THE SNOW WILL TAPER OFF OR WHEN...AND
WINDS LIKELY NEAR BLIZZARD CRITERIA WITH LIGHT SNOW ANYWAY...SO I
WILL RUN THE WARNING THROUGH TONIGHT AND WE CAN ADJUST THAT IF THE
ANSWER BECOMES EVIDENT. IN SOUTH PARK SNOW CONTINUES BUT EVENTUALLY
NE FLOW SHOULD SHUT IT OFF...WILL RUN THE WARNING THROUGH TODAY.
.LONG TERM...GREAT MAJORITY OF MODELS HAVE THE UPPER FEATURE
CENTERED OVER THE SOUTHERN TEXAS PANHANDLE ON SATURDAY AT 12Z. THE
NAM IS A BIT FURTHER NORTH BUT AGAIN ALL OF THEM ARE QUITE CLOSE.
BY SUNDAY 12Z THEY ALL HAVE IT OVER NORTHERN OKLAHOMA WITH THE UKMET
THE FURTHEST WEST OF THE BATCH. BY MONDAY MORNING 12Z A SHORT WAVE
RIDGE ALOFT IS OVER US WITH A TROUGH/CLOSED LOW OVER THE SOUTHERN
GREAT BASIN. THE QG VERTICAL VELOCITY FIELDS HAVE DECENT UPWARD
MOTION PROGGED OVER THE FORECAST AREA SATURDAY AND SATURDAY
EVENING. SOME LINGERS OVER THE NORTHEAST CORNER INTO SUNDAY MORNING
AS THE UPPER FEATURE PULLS AWAY. MOISTURE-WISE...THE NAM HAS PLENTY
SATURDAY THROUGH SUNDAY EVENING FOR THE PLAINS AND FOOTHILLS. THE
MOUNTAINS BEGIN DRYING OUT BY SUNDAY AFTERNOON. IN STARK CONTRAST
...THE GFS STARTS DRYING OUT THE WESTERN THREE-QUARTERS OF THE
FORECAST AREA BY SATURDAY MORNING. THE FAR EASTERN BORDER STAYS
MOIST. OVERNIGHT SATURDAY INTO SUNDAY...IT SHOWS VIRTUALLY NO
CLOUDINESS AT ALL FOR THE FORECAST AREA. VERY DRY SUNDAY TOO. IT'S
STRANGE THAT THE LOCATION OF ALL THE MAIN FEATURES OF THIS STORM ARE
NEARLY IDENTICAL BETWEEN THE NAM AND GFS...YET THE GFS' MOISTURE
GOES MISSING SOMETHING FIERCE. PERHAPS IT HAS SOMETHING TO DO WITH
SHRINKING PIECE OF ENERGY TO THE NORTH. THAT NORTHERN PIECE IS MORE
SIGNIFICANT ON THE GFS THROUGH SATURDAY NIGHT...WHICH MAY HELP CAUSE
THE MORE SIGNIFICANT DOWNSLOPING BY SATURDAY NIGHT. ANYWAY IT DOES
NOT SEEM TO MATTER ALL THAT MUCH AS THE GFS IS HAVING TROUBLE RIGHT
NOW WITH CURRENT MOISTURE/QPF. NEED TO LEAN WAY MORE TOWARDS THE
NAM WITH THIS MOISTURE ISSUE.
CONCERNING THE HIGHLIGHTS...THE DEEP UPSLOPE CIRCULATION GOES AWAY
DURING THE DAY SUNDAY. THE LOW LEVEL PRESSURE GRADIENT POINTS TO
BLIZZARD CONDITIONS FOR ABOUT THE EASTERN HALF OF THE PLAINS
SATURDAY...SATURDAY NIGHT...INTO SUNDAY. THE PLAINS CLOSER TO THE
FOOTHILLS AND THE FOOTHILLS THEMSELVES GET DOWNSLOPY EVEN ON THE NAM
BY SUNDAY. THE QPF FIELDS ARE ALSO PROBLEMATIC...WITH THE GFS
SHOWING BARELY ANY FOR THE FORECAST AREA...AND THE NAM PRETTY SPARSE
BY SATURDAY EVENING. AND AGAIN...ARE ANY OF THESE MODELS TIMING
THIS CLOSED SYSTEM ACCURATELY? A BLIZZARD WARNING FOR SOME OF THE
EASTERN PLAINS ZONES IS A GOOD BET INTO SUNDAY AFTERNOON ANYWAY.
WILL GO OVER IT WITH THE SHORT TERM MAN. IT WILL SNOW OVER THE REST
OF THE PLAINS SATURDAY INTO SUNDAY BUT WITH TOO MUCH UNCERTAINTY
ABOUT INTENSITY AND AMOUNTS...WILL...UNFORTUNATELY...HAVE TO KEEP A
WATCH GOING. WILL KEEP THE WATCH FOR THE FOOTHILLS AND MOUNTAINS
THROUGH SUNDAY DAWN. FOR TEMPERATURES...WILL LEAN MORE TOWARDS THE
NAM...A BIT COOLER. NO CHANGE FOR THE LATER DAYS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...SNOW AND BLOWING SNOW ADVISORY
THROUGH TONIGHT FOR THE FRONT RANGE MOUNTAINS...FOOTHILLS
...SOUTH PARK AND URBAN CORRIDOR NORTH OF DENVER...ZNES 33>39.
WINTER STORM WARNING THROUGH TONIGHT FOR URBAN CORRIDOR FROM
DENVER SOUTHWARD AND THE NORTHEAST PLAINS...ZONES 33>36..38>45.
BLIZZARD WARNING NOW THROUGH SUNDAY FOR ZONES 46>51.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY DAWN FOR ZONES
33>36.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY FOR ZONES 38>45.
&&
$$
COOPER/GIMMESTAD/RJKOOPMEINERS
FXUS65 KBOU 292202
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
300 PM MST FRI DEC 29 2006
.SHORT TERM...NOT MUCH IN TERMS OF SNOWFALL FOR THE FRONT RANGE THIS
AFTN AS THE SYSTEM REMAINS WELL TO THE SOUTH OF SCNTRL NEW MX.
BANDS OF SHOWERS THAT DID MOVE INTO THE URBAN CORRIDOR WEAKENED OR
DIMINISHED ENTIRELY. THIS SYSTEM IS STILL PROGGED TO MOVE IN THE TX
PANHANDLE BY 12Z SATURDAY...AND THOSE SHOWERS MAY ADD UP TO
ADDITIONAL SNOW TONIGHT INTO SATURDAY. BOTH THE GFS/WRF HOWEVER
KEEP WRN AND NRN PORTIONS OF THE CWFA FAIRLY DRY THROUGH SATURDAY.
QG OMEGA DOES INCREASE OVERNIGHT AS THE UPPER TROF MOVES TO NORTH
BUT IT IS FAIRLY WEAK. FLOW AOB 700 MB IS PROGGED TO BECOME MORE
NLY SO LESS UPSLOPE EXCEPT FOR AREAS ALONG THE PALMER DIVIDE. FOR
THIS REASON DECIDED TO DOWNGRADE THE WINTER STORM WARNING TO SNOW
AND BLOWING SNOW ADVISORY FOR THE URBAN CORRIDOR...SRN FRONT RANGE
FOOTHILLS AND ADJACENT PLAINS. BEST CHC FOR PCPN WILL BE EAST AND
SOUTH OF THE DENVER AREA WHERE BLIZZARD/WINTER STORM WARNING ARE
STILL IN EFFECT. FOCUS FOR MOST SNOWFALL WILL BE ALONG THE PALMER
DIVIDE WHERE BOTH FVBL QG OMEGA AND UPSLOPE EXISTS. SURFACE
PRESSURE GRADIENT IS PROGGED TO INCREASE LATE TNGT INTO SATURDAY FOR
THAT AREA. AS A RESULT WENT AHEAD OF ISSUED A BLIZZARD WARNING FOR
ZONE 41 THROUGH 6 PM SATURDAY...TO GO ALONG WITH ONGOING BLIZZARD
WARNING FOR THE ERN PLAINS.
.LONG TERM...MODELS REMAIN SIMILAR THROUGH SUNDAY WITH TRACK OF
UPPER LOW...WITH POSITION OVER CENTRAL OKLAHOMA BY 12Z SUNDAY AND
WESTERN MISSOURI BY 00Z MONDAY. EVEN THE UKMET AND LATEST DGEX ARE
COMING AROUND TO THIS SCENERIO. WRAPAROUND MOISTURE TO CONTEND WITH
SATURDAY NIGHT WITH DIV-Q VERTICAL VELOCITY PROGS SHOWING DECENT QG
ASCENT. SURFACE PROGS SHOW FLOW BECOMING NORTHWEST ALONG FRONT RANGE
BY MIDNIGHT...SO UPSLOPE FLOW MAY NOT BE AVAILABLE. MODEL SNOWFALL
SHOWING LIGHT AMOUNTS...LESS THAN 4 INCHES THROUGH 12Z SUNDAY. STILL
AN OUTSIDE CHANCE THAT FOOTHILLS AND ADJACENT PLAINS COULD SEE
ADDITIONAL AMOUNTS GIVEN POTENTIAL FOR ASCENT. THUS WILL KEEP WINTER
STORM WATCH GOING THROUGH 13Z SUNDAY. BLIZZARD WARNING STILL LOOKS
REASONABLE OVERNIGHT FAR NORTHEAST PLAINS SATURDAY NIGHT AS SURFACE
GRADIENT REMAINS TIGHT WITH 20 TO 30 KTS OF NORTHERLY WIND. WILL
DROP WATCH FOR MOUNTAINS AS MODEL CROSS SECTIONS SHOW A DRAMATIC
DROP IN MOISTURE WITH ONLY MINIMAL ASCENT. WILL ALSO LOWER POPS
THERE. ON SUNDAY...CHANCES LOOKING LESS FOR WRAPAROUND MOISTURE...
ESPECIALLY FOR MOUNTAINS AND ADJACENT PLAINS WITH DIV-Q VERTICAL
VELOCITY PROGS INDICATING QG DESCENT DURING THE DAY. EVEN IF LOW IS
SLOWER THAN CURRENT SOLUTIONS SUGGEST...DOESN'T LOOK SNOW AMOUNTS
WILL REACH ADVISORY CRITERIA. WILL DROP WATCH AS A RESULT. DOESN'T
APPEAR FAR EASTERN PLAINS WILL SUSTAIN BLIZZARD CRITERIA BUT AM
HESITANT TO DROP THE WARNING AT THIS TIME AS SURFACE PROGS SHOW
AROUND 25 KTS THROUGH THE DAY. SHOULD STILL BE SOME LIGHT SNOW
ONGOING IN THAT AREA SO BLOWING SNOW REMAINS A CONCERN. CONDITIONS
IMPROVE OVERNIGHT SUNDAY INTO MONDAY AS THE LOW HEADS EAST AND UPPER
RIDGE BUILDS OVER AREA.
FOR TUESDAY THROUGH FRIDAY...RIDGE TO DOMINATE THROUGH THURSDAY WITH
DRY CONDITIONS EXPECTED. LONG TERM MODELS SHOW WEAK SYSTEM AFFECTING
AREA FRIDAY AND WILL REINTRODUCE POPS FOR MOUNTAINS AT THAT TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING THROUGH
6 PM SATURDAY FOR MORGAN...ERN ADAMS AND ERN ARAPAHOE COUNTIES
ZONES 44 AND 45.
BLIZZARD WARNING THROUGH 6 PM SATURDAY FOR THE PALMER DIVIDE...
ZONE 41.
BLIZZARD WARNING THROUGH SUNDAY FOR ZONES 46>51.
SNOW AND BLOWING SNOW ADVISORY THROUGH 6 PM SATURDAY FOR THE SRN
FRONT RANGE FOOTHILLS..URBAN CORRIDOR..ADJACENT PLAINS
..ZONES 36 AND 38>43.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY DAWN FOR ZONES
35..36.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY DAWN FOR ZONES
38>45.
&&
$$
COOPER/LESZCYNSKI
FXUS65 KBOU 292213
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
312 PM MST FRI DEC 29 2006
.SHORT TERM...NOT MUCH IN TERMS OF SNOWFALL FOR THE FRONT RANGE THIS
AFTN AS THE SYSTEM REMAINS WELL TO THE SOUTH OF SCNTRL NEW MX.
BANDS OF SHOWERS THAT DID MOVE INTO THE URBAN CORRIDOR WEAKENED OR
DIMINISHED ENTIRELY. THIS SYSTEM IS STILL PROGGED TO MOVE IN THE TX
PANHANDLE BY 12Z SATURDAY...AND THOSE SHOWERS MAY ADD UP TO
ADDITIONAL SNOW TONIGHT INTO SATURDAY. BOTH THE GFS/WRF HOWEVER
KEEP WRN AND NRN PORTIONS OF THE CWFA FAIRLY DRY THROUGH SATURDAY.
QG OMEGA DOES INCREASE OVERNIGHT AS THE UPPER TROF MOVES TO NORTH
BUT IT IS FAIRLY WEAK. FLOW AOB 700 MB IS PROGGED TO BECOME MORE
NLY SO LESS UPSLOPE EXCEPT FOR AREAS ALONG THE PALMER DIVIDE. FOR
THIS REASON DECIDED TO DOWNGRADE THE WINTER STORM WARNING TO SNOW
AND BLOWING SNOW ADVISORY FOR THE URBAN CORRIDOR...SRN FRONT RANGE
FOOTHILLS AND ADJACENT PLAINS. BEST CHC FOR PCPN WILL BE EAST AND
SOUTH OF THE DENVER AREA WHERE BLIZZARD/WINTER STORM WARNING ARE
STILL IN EFFECT. FOCUS FOR MOST SNOWFALL WILL BE ALONG THE PALMER
DIVIDE WHERE BOTH FVBL QG OMEGA AND UPSLOPE EXISTS. SURFACE
PRESSURE GRADIENT IS PROGGED TO INCREASE LATE TNGT INTO SATURDAY FOR
THAT AREA. AS A RESULT WENT AHEAD OF ISSUED A BLIZZARD WARNING FOR
ZONE 41 THROUGH 6 PM SATURDAY...TO GO ALONG WITH ONGOING BLIZZARD
WARNING FOR THE ERN PLAINS.
.LONG TERM...MODELS REMAIN SIMILAR THROUGH SUNDAY WITH TRACK OF
UPPER LOW...WITH POSITION OVER CENTRAL OKLAHOMA BY 12Z SUNDAY AND
WESTERN MISSOURI BY 00Z MONDAY. EVEN THE UKMET AND LATEST DGEX ARE
COMING AROUND TO THIS SCENERIO. WRAPAROUND MOISTURE TO CONTEND WITH
SATURDAY NIGHT WITH DIV-Q VERTICAL VELOCITY PROGS SHOWING DECENT QG
ASCENT. SURFACE PROGS SHOW FLOW BECOMING NORTHWEST ALONG FRONT RANGE
BY MIDNIGHT...SO UPSLOPE FLOW MAY NOT BE AVAILABLE. MODEL SNOWFALL
SHOWING LIGHT AMOUNTS...LESS THAN 4 INCHES THROUGH 12Z SUNDAY. STILL
AN OUTSIDE CHANCE THAT FOOTHILLS AND ADJACENT PLAINS COULD SEE
ADDITIONAL AMOUNTS GIVEN POTENTIAL FOR ASCENT. THUS WILL KEEP WINTER
STORM WATCH GOING THROUGH 13Z SUNDAY. BLIZZARD WARNING STILL LOOKS
REASONABLE OVERNIGHT FAR NORTHEAST PLAINS SATURDAY NIGHT AS SURFACE
GRADIENT REMAINS TIGHT WITH 20 TO 30 KTS OF NORTHERLY WIND. WILL
DROP WATCH FOR MOUNTAINS AS MODEL CROSS SECTIONS SHOW A DRAMATIC
DROP IN MOISTURE WITH ONLY MINIMAL ASCENT. WILL ALSO LOWER POPS
THERE. ON SUNDAY...CHANCES LOOKING LESS FOR WRAPAROUND MOISTURE...
ESPECIALLY FOR MOUNTAINS AND ADJACENT PLAINS WITH DIV-Q VERTICAL
VELOCITY PROGS INDICATING QG DESCENT DURING THE DAY. EVEN IF LOW IS
SLOWER THAN CURRENT SOLUTIONS SUGGEST...DOESN'T LOOK SNOW AMOUNTS
WILL REACH ADVISORY CRITERIA. WILL DROP WATCH AS A RESULT. DOESN'T
APPEAR FAR EASTERN PLAINS WILL SUSTAIN BLIZZARD CRITERIA THOUGH
SURFACE PROGS SHOW AROUND 25 KTS THROUGH THE DAY. SHOULD STILL BE
SOME LIGHT SNOW ONGOING IN THAT AREA SO BLOWING SNOW COULD BE A
CONCERN. CONDITIONS IMPROVE OVERNIGHT SUNDAY INTO MONDAY AS
THE LOW HEADS EAST AND UPPER RIDGE BUILDS OVER AREA.
FOR TUESDAY THROUGH FRIDAY...RIDGE TO DOMINATE THROUGH THURSDAY WITH
DRY CONDITIONS EXPECTED. LONG TERM MODELS SHOW WEAK SYSTEM AFFECTING
AREA FRIDAY AND WILL REINTRODUCE POPS FOR MOUNTAINS AT THAT TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING THROUGH
6 PM SATURDAY FOR MORGAN...ERN ADAMS AND ERN ARAPAHOE COUNTIES
ZONES 44 AND 45.
BLIZZARD WARNING THROUGH 6 PM SATURDAY FOR THE PALMER DIVIDE...
ZONE 41.
BLIZZARD WARNING THROUGH SUNDAY DAWN FOR ZONES 46>51.
SNOW AND BLOWING SNOW ADVISORY THROUGH 6 PM SATURDAY FOR THE
SRN FRONT RANGE FOOTHILLS..URBAN CORRIDOR..ADJACENT PLAINS
..ZONES 36 AND 38>43.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY DAWN FOR ZONES
35..36.
WINTER STORM WATCH SATURDAY THROUGH SUNDAY DAWN FOR ZONES
38>45.
&&
$$
COOPER/LESZCYNSKI
FXUS65 KBOU 300442
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
940 PM MST FRI DEC 29 2006
UPDATE...SNOW HAS DECREASED CONSIDERABLY THIS EVENING AS DRY AIR IS
SIMPLY COMING IN TOO FAST FROM THE NORTH. LOOKS LIKE DISTURBANCE IN
THE NORTHERN BRANCH THAT WE TALKED ABOUT FOR THE LAST SEVERAL DAYS
IS RESPONSIBLE FOR THIS. AS A RESULT...HAVE DROPPED ALL HIGHLIGHTS
OVER THE FRONT RANGE URBAN CORRIDOR. THERE IS STILL A THREAT OF
HEAVIER SNOWFALL MOVING BACK ACROSS THE PLAINS TOMORROW AND TOMORROW
NIGHT BUT EVEN THIS LOOKS TO BE FADING A BIT AS UPPER LOW WANTS TO
MOVE MORE EASTWARD INTO THE SOUTHERN HIGH PLAINS...JUST A BIT TOO
FAR SOUTH FOR OPTIMAL LOCATION FOR HEAVY SNOW IN OUR FORECAST AREA.
.SHORT TERM...NOT MUCH IN TERMS OF SNOWFALL FOR THE FRONT RANGE THIS
AFTN AS THE SYSTEM REMAINS WELL TO THE SOUTH OF SCNTRL NEW MX.
BANDS OF SHOWERS THAT DID MOVE INTO THE URBAN CORRIDOR WEAKENED OR
DIMINISHED ENTIRELY. THIS SYSTEM IS STILL PROGGED TO MOVE IN THE TX
PANHANDLE BY 12Z SATURDAY...AND THOSE SHOWERS MAY ADD UP TO
ADDITIONAL SNOW TONIGHT INTO SATURDAY. BOTH THE GFS/WRF HOWEVER
KEEP WRN AND NRN PORTIONS OF THE CWFA FAIRLY DRY THROUGH SATURDAY.
QG OMEGA DOES INCREASE OVERNIGHT AS THE UPPER TROF MOVES TO NORTH
BUT IT IS FAIRLY WEAK. FLOW AOB 700 MB IS PROGGED TO BECOME MORE
NLY SO LESS UPSLOPE EXCEPT FOR AREAS ALONG THE PALMER DIVIDE. FOR
THIS REASON DECIDED TO DOWNGRADE THE WINTER STORM WARNING TO SNOW
AND BLOWING SNOW ADVISORY FOR THE URBAN CORRIDOR...SRN FRONT RANGE
FOOTHILLS AND ADJACENT PLAINS. BEST CHC FOR PCPN WILL BE EAST AND
SOUTH OF THE DENVER AREA WHERE BLIZZARD/WINTER STORM WARNING ARE
STILL IN EFFECT. FOCUS FOR MOST SNOWFALL WILL BE ALONG THE PALMER
DIVIDE WHERE BOTH FVBL QG OMEGA AND UPSLOPE EXISTS. SURFACE
PRESSURE GRADIENT IS PROGGED TO INCREASE LATE TNGT INTO SATURDAY FOR
THAT AREA. AS A RESULT WENT AHEAD OF ISSUED A BLIZZARD WARNING FOR
ZONE 41 THROUGH 6 PM SATURDAY...TO GO ALONG WITH ONGOING BLIZZARD
WARNING FOR THE ERN PLAINS.
.LONG TERM...MODELS REMAIN SIMILAR THROUGH SUNDAY WITH TRACK OF
UPPER LOW...WITH POSITION OVER CENTRAL OKLAHOMA BY 12Z SUNDAY AND
WESTERN MISSOURI BY 00Z MONDAY. EVEN THE UKMET AND LATEST DGEX ARE
COMING AROUND TO THIS SCENERIO. WRAPAROUND MOISTURE TO CONTEND WITH
SATURDAY NIGHT WITH DIV-Q VERTICAL VELOCITY PROGS SHOWING DECENT QG
ASCENT. SURFACE PROGS SHOW FLOW BECOMING NORTHWEST ALONG FRONT RANGE
BY MIDNIGHT...SO UPSLOPE FLOW MAY NOT BE AVAILABLE. MODEL SNOWFALL
SHOWING LIGHT AMOUNTS...LESS THAN 4 INCHES THROUGH 12Z SUNDAY. STILL
AN OUTSIDE CHANCE THAT FOOTHILLS AND ADJACENT PLAINS COULD SEE
ADDITIONAL AMOUNTS GIVEN POTENTIAL FOR ASCENT. THUS WILL KEEP WINTER
STORM WATCH GOING THROUGH 13Z SUNDAY. BLIZZARD WARNING STILL LOOKS
REASONABLE OVERNIGHT FAR NORTHEAST PLAINS SATURDAY NIGHT AS SURFACE
GRADIENT REMAINS TIGHT WITH 20 TO 30 KTS OF NORTHERLY WIND. WILL
DROP WATCH FOR MOUNTAINS AS MODEL CROSS SECTIONS SHOW A DRAMATIC
DROP IN MOISTURE WITH ONLY MINIMAL ASCENT. WILL ALSO LOWER POPS
THERE. ON SUNDAY...CHANCES LOOKING LESS FOR WRAPAROUND MOISTURE...
ESPECIALLY FOR MOUNTAINS AND ADJACENT PLAINS WITH DIV-Q VERTICAL
VELOCITY PROGS INDICATING QG DESCENT DURING THE DAY. EVEN IF LOW IS
SLOWER THAN CURRENT SOLUTIONS SUGGEST...DOESN'T LOOK SNOW AMOUNTS
WILL REACH ADVISORY CRITERIA. WILL DROP WATCH AS A RESULT. DOESN'T
APPEAR FAR EASTERN PLAINS WILL SUSTAIN BLIZZARD CRITERIA THOUGH
SURFACE PROGS SHOW AROUND 25 KTS THROUGH THE DAY. SHOULD STILL BE
SOME LIGHT SNOW ONGOING IN THAT AREA SO BLOWING SNOW COULD BE A
CONCERN. CONDITIONS IMPROVE OVERNIGHT SUNDAY INTO MONDAY AS
THE LOW HEADS EAST AND UPPER RIDGE BUILDS OVER AREA.
FOR TUESDAY THROUGH FRIDAY...RIDGE TO DOMINATE THROUGH THURSDAY WITH
DRY CONDITIONS EXPECTED. LONG TERM MODELS SHOW WEAK SYSTEM AFFECTING
AREA FRIDAY AND WILL REINTRODUCE POPS FOR MOUNTAINS AT THAT TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING THROUGH
6 PM SATURDAY FOR MORGAN AND EASTERN PORTIONS OF ADAMS AND
ARAPAHOE COUNTIES...ZONES 44 AND 45.
BLOWING SNOW ADVISORY NORTHEASTERN WELD COUNTY UNTIL 6 PM
SATURDAY...ZONE 42.
BLIZZARD WARNING THROUGH 6 PM SATURDAY FOR THE PALMER DIVIDE...
ZONE 41.
BLIZZARD WARNING THROUGH 6 AM SUNDAY FOR THE FAR EASTERN
PLAINS...ZONES 46>51.
&&
$$
BARJENBRUCH/COOPER/LESZCYNSKI