Area Forecast Discussion (National Weather Service)
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
345 AM MST WED MAR 10 2010
.SHORT TERM...OUR AREA WILL REMAIN PINCHED BETWEEN THE LOW OVER
NEBRASKA AND SOUTH DAKOTA AND TWO LOWS MOVING ACROSS ARIZONA AND NEW
MEXICO THROUGH TONIGHT. THE LOW TO OUR NORTHEAST IS GETTING PRETTY
WRAPPED UP AND THE DEFORMATION ZONE OVER THE NORTHEAST CORNER OF
COLORADO IS NOT EXPECTED TO MOVE MUCH. LIFT IN THIS AREA IS PRETTY
LIGHT BUT THERE WILL STILL BE SOME WEAK SHOWER ACTIVITY. BETWEEN THE
LOW IS A DRIER AREA THOUGH THERE WILL STILL BE SOME CLOUDS. DENVER
WILL BE IN THIS REGION TODAY. CLOUD SHIELD ON THE NORTH SIDE OF THE
LOW NOW OVER NEW MEXICO WILL SHIFT EASTWARD SOUTH OF INTERSTATE 70
KEEPING SOME SHOWERS ACROSS LINCOLN COUNTY. THE NEXT LOW LOOKS TO BE
FOLLOWING A SIMILAR TRACK FOR TONIGHT...AND IT NOW LOOKS LIKE MOST
OF THE LIFT FROM THAT SYSTEM WILL ALSO BE SOUTH OF OUR AREA...WITH
SOME INFLUENCE ON THE WESTERN AND SOUTHERN FRINGES ONCE AGAIN. THE
FLY IN THE OINTMENT TODAY IS DIURNAL CONVECTION. THERE WAS DECENT
CONVECTION YESTERDAY OVER THE MOUNTAINS...WHILE THE SUNNY AREA OF
THE PLAINS HAD DRIED OUT TOO MUCH TO SUPPORT MORE THAN ISOLATED
SHOWERS. MODELS CONTINUE TO TRY TO PUT CONVECTION ACROSS DENVER AND
BOULDER TODAY WITH SEVERAL INCHES OF SNOW SHOWN FOR THIS EVENING.
THERE MAY BE SOME RECOVERY OF THE MOISTURE AS WEAK NORTHERLY LOW
LEVEL FLOW STRENGTHENS A BIT. HOWEVER...CONVECTIVE FOCUS SHOULD
STILL BE OVER THE MOUNTAINS AND THE PROPAGATION SHOULD BE SOUTHWARD
OR CLOSE TO IT. SINCE THE LARGER SCALE FORCING IS HEADED SOUTH
AGAIN...I WILL DROP BACK TO SCATTERED POPS FOR DENVER EXPECTING MOST
OF THE SHOWERS TO BE WEST AND SOUTH OF THE CITY. SNOW ACCUMULATIONS
FOR THOSE AREAS MAY BE A BIT MUCH IF WE DO NOT GET HELP FROM THE
NEXT LOW...BUT WE WILL HAVE TO SEE HOW MUCH LOW LEVEL CONVERGENCE
THERE IS THIS EVENING. IT SHOULD STILL BE WARM ENOUGH FOR SOME RAIN
SHOWERS MIXED IN ON THE PLAINS DURING THE DAY TODAY.
.LONG TERM...THE BROAD UPPER TROUGH OVER THE FORECAST AREA PUSHES
OUT THROUGH THE DAY THURSDAY WITH INCREASING NORTHERLY FLOW ALOFT
THROUGH THE DAY. THE NORTHERLY FLOW ALOFT CONTINUES TO INCREASE
THURSDAY NIGHT WITH A WEAK JET MAXIMUM OVER THE FORECAST AREA AT 12Z
FRIDAY MORNING. A HIGH AMPLITUDE UPPER RIDGE MOVES INTO COLORADO
FRIDAY...WITH IT`S AXIS GETTING OVER THE FORECAST AREA BY 12Z
SATURDAY MORNING. SO THE FLOW ALOFT DECREASES THROUGH THE DAY
FRIDAY AND FRIDAY NIGHT. WEAK DOWNWARD VERTICAL VELOCITY IS PROGGED
OVER THE FORECAST AREA THURSDAY THROUGH MUCH OF FRIDAY NIGHT...
BEFORE WEAK UPWARD MOTION MOVES INTO THE WESTERN FORECAST AREA BY
12Z SATURDAY MORNING. THE BOUNDARY LAYER FLOW LOOKS TO BE FAIRLY
STRONG THURSDAY THROUGH FRIDAY FROM THE NORTH-NORTHWEST. FRIDAY
NIGHT THE LOW LEVEL GRADIENT WEAKENS WITH NORMAL DIURNAL WIND
PATTERNS EXPECTED. FOR MOISTURE...THERE IS SOME OVER THE EASTERN
PLAINS AND MOUNTAINS ON THURSDAY...NOTHING DOWN LOW OVER THE
FOOTHILLS OR WESTERN PLAINS. THE NAM DRIES OUT EVERYWHERE BY
THURSDAY EVENING ..THE GFS LAGS A BIT BEHIND. FRIDAY IS PRETTY
DRY...WITH JUST A TAD OF LOW LEVEL MOISTURE OVER THE MOUNTAINS.
FRIDAY NIGHT IS VERY DRY. THERE IS NO CAPE PROGGED OVER THE
FORECAST AREA THROUGH THE PERIODS. THE NAM QPF FIELDS HAVE A TAD OF
MEASURABLE SNOW IN THE MOUNTAINS ON THURSDAY. THE GFS HAS THE
SAME...WITH A BIT OUT ON THE PLAINS AS WELL IN THE MORNING. THE GFS
ALSO KEEPS A SMALL BIT IN THE MOUNTAINS THURSDAY NIGHT...THE NAM IS
DRY. BOTH MODELS HAVE NONE FRIDAY OR FRIDAY NIGHT. FOR POPS IN THE
MOUNTAINS...MOST PARAMETERS POINT TO SNOW...THE MOISTURE IS JUST NOT
REAL DEEP. WILL GO "CHANCE" OF SNOW THURSDAY...AND "SLIGHT CHANCE"
THURSDAY NIGHT...NO POPS FRIDAY AND FRIDAY NIGHT. FOR THE PLAINS
...WILL HAVE SOME 10-30%S LINGERING IN THE MORNING THURSDAY...
NOTHING FOR THE FOOTHILLS AND ADJACENT PLAINS. THURSDAY AFTERNOON
THROUGH FRIDAY NIGHT...NO POPS OVER THE PLAINS. FOR TEMPERATURES
...THURSDAY`S HIGHS ARE A TAD WARMER THAN TODAY`S. FRIDAY`S HIGHS
WARM-UP 3-4 C FROM THURSDAY`S. FOR THE LATER DAYS...SATURDAY
THROUGH TUESDAY...THERE IS UPPER RIDGING FOR SATURDAY. LATER
SATURDAY NIGHT INTO SUNDAY...MODELS HAVE AN UPPER CLOSED LOW NEAR
THE FOUR CORNERS MOVING SOUTH. BY MONDAY MORNING 12Z...THIS UPPER
LOW IS OVER NORTH CENTRAL MEXICO...JUST SOUTH OF THE NEW
MEXICO/TEXAS BORDER. FOR MONDAY...WEAK UPPER TROUGHING IS OVER
COLORADO WITH WEAK FLOW ALOFT. ON TUESDAY...WEAK NORTHERLY FLOW
ALOFT IS PROGGED WITH AN UPPER RIDGE TO THE IMMEDIATE WEST. BOTH
THE GFS AND ECMWF HAVE MOISTURE AND UPSLOPE FOR THE CWA LATE
SATURDAY NIGHT INTO MONDAY. WILL GO WITH A "SLIGHT CHANCE" ALL
AREAS. DRY ON TUESDAY. OF NOTE...THE GFS HAS COME AROUND SOMEWHAT
TO THE ECMWF WITH THIS FEATURE...WE`LL SEE.
&&
.AVIATION...SCATTERED SHOWERS ARE EXPECTED TO DEVELOP THIS AFTERNOON
AND EVENING...WITH MAINLY SNOW. THE SHOWERS WILL BE MORE NUMEROUS
SOUTH AND WEST OF DENVER. INSTRUMENT APPROACHES WILL LIKELY BE
NEEDED AT TIMES...AND THERE IS A CHANCE OF BRIEF IFR CONDITIONS IN
SHOWERS. THE SHOWER ACTIVITY WILL DIMINISH OVERNIGHT. MINOR SNOW
ACCUMULATIONS ARE POSSIBLE FROM THE SHOWERS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
$$
GIMMESTAD/RJK
Dry 
