Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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102
FXUS65 KBOU 010920
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
320 AM MDT SUN MAY 1 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 230 AM MDT SUN MAY 1 2016

THIS MORNING...A WEAK DEFORMATION FIELD WILL BE OVER THE CWA WITH
BETWEEN THE TROUGH OVER SOUTHEAST NEBRASKA AND THE NEXT UPPER LOW
OVER CENTRAL ARIZONA. LOW CLOUDS AND LIGHT SNOW HAVE CONTINUED
OVERNIGHT BUT MINIMAL IF ANY ACCUMULATIONS. WILL KEEP SCT COVERAGE
IN MOST AREAS THIS MORNING. BY THIS AFTERNOON...LOW LEVELS
DESTABILIZE WITH AFTN HEATING AND SHOULD SEE PCPN COVERAGE
INCREASE FROM THE SOUTH AND SOUTHWEST. MID AND UPPER LEVEL
MOISTURE DOES INCREASE AHEAD OF THE NEXT SYSTEM...BUT THE CLOSED
SYSTEM OPENS UP...WEAKENS AND WASHES OUT AS IT SHIFTS EASTWARD
THIS AFTN AND EVENING. BEST QG ASCENT ASSOCIATED WITH THE TROUGH
OVER ARIZONA WILL BE WELL TO THE SOUTH OVER NEW MEXICO TODAY. WEAK
QG ASCENT IN THE MID LEVELS ASSOCIATED WITH THIS TROF...COUPLED
SHALLOW CONVECTION THIS AFTN WILL BE ENOUGH TO PRODUCE ANOTHER
ROUND OF PCPN. OVERALL SNOWFALL WILL BE LIGHT IN THE MOUNTAINS AND
FOOTHILLS HOWEVER WITH THE BEST POTENTIAL SOUTH OF THE I-70
CORRIDOR. COULD SEE MINIMAL ACCUMULATIONS OF 1-2 INCHES OVER THE
PALMER DIVIDE AS WELL LATE THIS AFTN/EVNG. THE MDLS SHOW PCPN
DIMINISHING OVERNIGHT WITH DECREASING CLOUDINESS FM NORTH TO SOUTH
AFTER 06Z. CONCERN LATE TONIGHT WILL INVOLVE TEMPERATURES DROPPING
BELOW FREEZING...SO WILL PROBABLY NEED TO LOOK INTO A FROST/FREEZE
ADVSY AT SOME POINT LATER TODAY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 230 AM MDT SUN MAY 1 2016

AN UPPER LEVEL HIGH WILL BE OVER THE NRN ROCKIES WITH WEAK FLOW
ALOFT OVER THE AREA AS THE STRONGER FLOW ALOFT STAYS WELL SOUTH.
THERE WILL STILL BE SOME LINGERING MOISTURE AND WITH AFTN HEATING
SHOULD SEE A CHC OF SHOWERS OVER THE HIGHER TERRAIN. ACROSS NERN
CO IT WILL BE DRY ALTHOUGH THERE COULD BE A FEW AFTN SHOWERS
ACROSS THE PALMER DIVIDE AND WRN AREAS OF THE URBAN CORRIDOR.
HIGHS WILL MODERATE INTO THE 50S ACROSS NERN CO.

FOR MON NIGHT A WEATHER SYSTEM WILL MOVE SOUTHWARD ACROSS THE
CENTRAL PLAINS WITH THE WRN EXTENT OF THIS FEATURE POSSIBLY
AFFECTING THE FAR NERN PLAINS.  THIS WILL MENTION A SLIGHT CHC OF
SHOWERS MAINLY AFTER MIDNIGHT.  ACROSS THE HIGHER TERRAIN SHOWERS
SHOULD END BY EARLY EVENING.

BY TUE AN UPPER LEVEL RIDGE WILL BE ACROSS THE AREA WITH WEAK FLOW
ALOFT.  ONCE AGAIN THERE WILL BE SOME LINGERING MOISTURE MAINLY OVER
THE HIGHER TERRAIN WHICH MAY LEAD TO A SLIGHT CHC OF SHOWERS IN THE
AFTN/EARLY EVENING HOURS.  ACROSS NERN CO IT WILL REMAIN DRY WITH
TEMPS FINALLY RISING BACK TO SEASONAL LEVELS IN THE 60S.  FOR WED
THE UPPER LEVEL RIDGE WILL REMAIN ACROSS COLORADO WITH A DRIER
AIRMASS AS WELL SO WILL ONLY MENTION ISOLD AFTN SHOWERS IN THE MTNS.
TEMPS WILL CONTINUE TO RISE AS READINGS RISE INTO THE UPPER 60S TO
MID 70S ACROSS THE PLAINS.

ON THU TWO STG STORM SYSTEMS WILL BE AFFECTING THE US WITH ONE OVER
THE EAST AND ANOTHER ALONG THE WEST COAST.  IN BETWEEN THESE SYSTEMS
AN UPPER LEVEL RIDGE WILL REMAIN ACROSS THE AREA.  AS THE FLOW ALOFT
BECOMES MORE SSW SOME MOISTURE MAY BE EMBEDDED IN THE FLOW.  THIS
MOISTURE COMBINED WITH STEEP LAPSE RATES MAY LEAD TO A SLIGHT CHC OF
CONVECTION OVER THE HIGHER TERRAIN THU AFTN.  ACROSS THE PLAINS IT
WILL REMAIN DRY WITH HIGHS IN THE 70S.

BY FRI A STORM SYSTEM WILL BE OVER THE SWRN US WITH INCREASING SSW
FLOW ALOFT OVER THE AREA.  THERE WILL LIKELY BE SOME MINOR
DISTURBANCES EMBEDDED IN THE FLOW AND COMBINED WITH FAVORABLE LAPSE
RATES SHOULD SEE SOME WDLY SCT CONVECTION OVER THE HIGHER TERRAIN.
AT THE SFC LOW PRES WILL LIKELY BE FURTHER WEST THAN SHOWN BY MODELS
WHICH WILL ALLOW FOR INCREASING MOIST SSE LOW LVL FLOW ACROSS THE
PLAINS.  IF A DENVER CYCLONE FORMS ALLOWING FOR AN ENHANCED
CONVERGENCE ZONE THEN COULD SEE A FEW STRONGER STORMS BY LATE
AFTN INTO THE EARLY EVENING AS CAPES RISE TO THE 1000-1500 J/KG
RANGE ACROSS THE PLAINS.

FOR SAT THE UPPER LEVEL LOW WILL BE OVER SWRN UTAH/NWRN ARIZONA WITH
STG SLY FLOW ALOFT ACROSS THE AREA.  A SFC LOW WILL PROBABLY STILL
BE CENTERED CLOSER TO THE FOOTHILLS AS THE MODELS LIKELY HAVE THE
LOW TO FAR EAST ALONG WITH A PSEUDO DRYLINE. AS A RESULT EXPECT
DEEPER LOW LVL MOISTURE TO REMAIN OVER THE PLAINS WITH A VERY
UNSTABLE AIRMASS BY SAT AFTN WITH CAPES AOA 2000 J/KG. THERE WILL
LIKELY BE A FEW DISTURBANCES MOVING ACROSS THE AREA AS WELL TO
ENHANCE THE POTENTIAL FOR STRONG STORMS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 230 AM MDT SUN MAY 1 2016

ILS RESTRICTIONS WITH OCNL MVFR RESTRICTIONS ANTICIPATED THROUGH
THIS EVENING. VERY LGT PCPN HAS NOT RESTRICTED VSBYS AT THE
AIRPORTS THIS THIS MORNING BUT CIGS AOB 3K FT AGL LIKELY THIS
MORNING. PCPN THAT DEVELOPS THIS AFTN WL BE A MIX OF RAIN/SNOW AND
WILL BE MORE CONVECTIVE THIS AFTN/EVNG. OVERALL LGT-MDT SHOWERS
SO DO NOT EXPECT VSBYS TO BE RESTRICT MUCH...MAYBE 3-5 MILES IN
THE HEAVIER SHOWERS. CIGS WILL LIFT LATER THIS EVENING...WITH
DECREASING CLOUDINESS AFTER 06Z. NORTHWEST/NORTHERLY WINDS
TODAY...MAY BECOME NORTH/NORTHEASTERLY 23-01Z TIME FRAME. BEST
WINDOW FOR SHOWERS TODAY WILL BE IN THE 21-02 TIME FRAME...WITH
PRIMARILY MVFR CIG RESTRICTIONS EXPECTED THROUGH THIS EVENING.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...COOPER
LONG TERM...RPK
AVIATION...COOPER



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