Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 231652
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1052 AM MDT WED APR 23 2014

.UPDATE...
ISSUED AT 1052 AM MDT WED APR 23 2014

CURRENT FORECASTS STILL LOOK ON TRACK. UPPER TROUGH CURRENTLY
OVER GREAT BASIN WITH SOUTHWEST FLOW ACROSS COLORADO. INCREASING
MID LEVEL ASCENT AND WEAK INSTABILITY AHEAD OF THE TROUGH
GENERATING A FEW SHOWERS ACROSS THE MOUNTAINS. OVER THE PLAINS...
LAPS ANALYSIS SHOWING SURFACE LOW OVER SOUTHEAST COLORADO
BEGINNING TO INTENSIFY A BIT. WINDS ACROSS THE PLAINS BECOMING A
BIT MORE NORTHWEST FROM ROUGHLY DENVER AND LIMON NORTHWARD WHILE
STILL MORE SOUTHWESTERLY ALONG THE PALMER DIVIDE. TROUGH TO MOVE
INTO COLORADO THIS AFTERNOON AND OVER THE EASTERN PLAINS DURING
THE EVENING. STILL EXPECTING A BIT MORE SHOWER COVERAGE OVER THE
MOUNTAINS. CAPE VALUES LIMITED...BUT WILL KEEP THE MENTION OF
THUNDER DUE TO COLDER MID LEVEL TEMPS AND LIFT WITH TROUGH. LOOKS
TO BE A BETTER CHANCE FOR MEASURABLE RAINFALL...WITH SOME SNOW
POSSIBLE HIGHER PASSES. ACROSS THE PLAINS...WINDS TO BECOME
NORTHWEST WINDS DURING THE AFTERNOON...MORE NORTHERLY BY THE
EVENING. SOME SHOWERS STILL POSSIBLE THIS AFTERNOON AND EVENING
WITH TROUGH PASSAGE. ANY CHANCE FOR THUNDER APPEARS TO BE EAST OF
A STERLING TO LIMON LINE WHERE CAPES EXPECTED TO BE AROUND 100-200
J/KG. NOT ALOT OF LOW LEVEL MOISTURE ON FORECAST SOUNDINGS...SO
SHOWERS OR STORMS THAT DEVELOP WILL PRODUCE GUSTY WINDS BUT LITTLE
RAINFALL.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 317 AM MDT WED APR 23 2014

UPPER LEVEL TROUGH WILL MOVE ACROSS THE GREAT BASIN THIS MORNING AND
INTO COLORADO THIS AFTERNOON. THE TROUGH WILL CONTINUE EASTWARD
TONIGHT AND EXIT THE STATE BY THURSDAY MORNING. A SURFACE LOW WILL
DEEPEN OVER SOUTHEAST COLORADO TODAY. THIS WILL CAUSE SOUTHERLY
WINDS OVER NORTHEAST COLORADO TO TURN WESTERLY DURING THE LATE
MORNING HOURS AND THEN NORTHWEST TO NORTHERLY DURING THE AFTERNOON
AND EVENING. THE NORTHWEST WINDS WILL PULL IN COOLER AIR THIS
AFTERNOON. HIGHS WILL BE COOLER TODAY...BUT STILL SLIGHTLY ABOVE
NORMAL. SOUTHERN LINCOLN COUNTY WILL SEE SOUTHWESTERLY WINDS FOR
MUCH OF THE AFTERNOON. THIS WILL PUSH HIGHS CLOSE TO 80 DEGREES. THE
GUSTY SOUTHERLY WINDS AND LOW RELATIVE HUMIDITIES WILL PRODUCE RED
FLAG CONDITIONS.

LIFT AHEAD OF THE TROUGH HAS PRODUCED SCATTERED SHOWERS A FEW
THUNDERSTORMS OVER NORTHWEST COLORADO EARLY THIS MORNING. AS THE
TROUGH PROGRESSES EASTWARD...SO WILL THE CHANCE FOR SHOWERS AND
THUNDERSTORMS. NOT A LOT OF MOISTURE WITH THIS SYSTEM...ESPECIALLY
AT THE LOWER LEVELS...SO THE CHANCE FOR PRECIPITATION WILL REMAIN
LOW 10-40 PERCENT. BY MIDNIGHT...THE LIFT AHEAD OF THE TROUGH WILL
BE EAST OF THE STATE SO EXPECT THE CHANCE FOR SHOWERS TO END BY
THEN.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 317 AM MDT WED APR 23 2014

WLY FLOW ALOFT WILL BE OVER THE RGN ON THU AS ONLY SOME HIGHER LVL
MOISTURE MOVES ACROSS. SHOULD SEE A DRY DAY WITH AFTN HIGHS IN
THE 65 TO 70 DEGREE RANGE OVER NERN CO. GUSTY WNW WINDS WILL BE
POSSIBLE IN THE AFTN ALONG THE WY BORDER AND ACROSS THE FAR NERN
PLAINS.

BY FRI THE FLOW ALOFT WILL BECOME MORE WSW AS A STG UPPER LEVEL
TROUGH APPROACHES THE WEST COAST. OUTSIDE OF SOME MID AND HIGH
CLOUDS WILL KEEP THE FCST DRY THRU FRI NIGHT.  SFC LOW PRES WILL
GRADUALLY INTENSIFY FM CNTRL WY INTO CNTRL CO WITH GUSTY SSE WINDS
DEVELOPING BY AFTN OVER NERN CO.  AFTN HIGHS WILL BE IN THE 70S OVER
NERN CO WITH LOW HUMIDITY VALUES SO COULD SEE AN INCREASE IN FIRE
DANGER OVER THE PALMER DIVIDE AND PORTIONS OF THE PLAINS.

FOR THE WEEKEND THE MEDIUM RANGE MODELS CONTINUE TO YO-YO THEIR
FORECASTS. TWO NIGHTS AGO THEY WERE TRENDING TOWARDS A STG CLOSED
LOW DEVELOPING OVER SERN CO BY SUN WHILE LAST NIGHT AND YESTERDAY
MORNING THEY HAD THIS LOW FURTHER NORTH OVER NRN CO/WY. TONIGHT
THEY ARE ALL NOW TRENDING BACK TOWARDS A SOUTHERN TRACK WITH A STG
UPPER LEVEL LOW BECOMING VERTICALLY STACKED OVER SERN CO ON SUN.
SUFFICE TO SAY THE FCST IS STILL NOT VERY CLEAR AS TO WHERE THIS
STG UPPER LEVEL LOW WILL END UP BY SUN.

AT ANY RATE AHEAD OF THIS SYSTEM ON SAT STG SFC LOW PRES WILL
INTENSIFY OVER COLORADO.  AT THIS POINT CONSIDERING HOW MUCH THE
FLOW WILL BACK AHEAD OF THE STG UPPER LEVEL TROUGH NONE OF THEM
MODELS SEEM TO HAVE A CLUE WITH RESPECT TO WHERE THE MAIN SFC LOW
WILL BE.  WITH THE MAIN UPPER LEVEL LOW FCST TO BE OVER NERN AZ/NWRN
NM BY SAT EVENING WOULD THINK MAIN SFC LOW WILL HANG BACK CLOSER TO
THE FOOTHILLS AND NOT RESIDE OVER THE ERN PLAINS.  AS A RESULT THIS
SHOULD ALLOW FOR SELY INFLOW OF DEEPER LOWER LEVEL MOISTURE ACROSS
THE PLAINS BY LATE AFTN INTO THE EVENING HOURS WITH A POTENTIAL
TRIPLE POINT SOMEWHERE TO THE NORTHEAST OR EAST OF DENVER.  WITH
SOUNDINGS SHOWING EXCELLENT MID LVL SHEAR AND HIGH HELICITY VALUES
ONE WOULD THINK THERE WOULD BE SOME POTENTIAL FOR SVR STORMS LATE
SAT AFTN INTO SAT NIGHT OVER PORTIONS OF THE NERN PLAINS AS MAIN
UPPER LEVEL TROUGH APPROACHES. ELSEWHERE WITH DECENT LAPSE RATES
IN THE MTNS AND INCREASING MID LVL QG ASCENT BY LATE AFTN SHOULD
SEE A CHC OF SHOWERS/TSTMS AS WELL UNLESS SYSTEM ENDS UP BEING
SLOWER THAT FCST. MEANWHILE HIGH TEMPS OVER NERN CO MAY RISE BACK
INTO THE LOWER TO MID 70S AS 850-700 MB TEMPS ARE SIMILAR TO
FRIDAY.

FOR SUN AS MENTIONED ABV THE WHOLE FCST DEPENDS ON WHERE A STG
CLOSED LOW DVLPS.  IF IT DOES TAKE A MORE SRN ROUTE INTO SERN CO
THEN THAT WOULD SET THE STAGE FOR A SPRING STORM OVER NRN CO.  THE
ONE THING THAT IS LACKING IS COLD AIR WITH THIS SYSTEM SO PCPN
ACROSS NERN CO AND MOST OF THE FOOTHILLS WOULD BE ALL RAIN THRU SUN
AFTN WITH THE THREAT OF HEAVY SNOW CONFINED TO THE MTNS.  AT THIS
TIME CAN NOT IGNORE THE FACT THAT A STG STORM SYSTEM MAY END UP OVER
SERN CO SO WILL BUMP POPS UP INTO CHC CATEGORY FOR NERN CO/FOOTHILLS
AND LIKELY FOR THE MTNS.  AS FOR HIGHS WILL KEEP READINGS IN THE 50S
OVER NERN CO.

BY SUN NIGHT THE CLOSED LOW IS FCST TO MOVE SLOWLY INTO WRN KANSAS
AND THEN INTO CENTRAL KANSAS BY MON AFTN BASED ON CURRENT DATA.  IF
THIS OCCURS THEN SIGNIFICANT PCPN COULD LINGER INTO MON MORNING OVER
NRN CO BEFORE GRADUALLY ENDING BY MIDDAY MON.  THUS HAVE RAISED POPS
FOR SUN NIGHT ACROSS THE CWA.  TEMPS WILL BECOME COLDER SUN NIGHT SO
PCPN SHOULD BECOME ALL SNOW IN THE FOOTHILLS AND OVER THE PALMER
DIVIDE WITH A RAIN/SNOW MIX POSSIBLE OVER NERN CO AFTER MIDNIGHT.
AS FOR HIGHS ON MON WILL KEEP READINGS MOSTLY IN THE 50S OVER NERN
CO.

FOR MON NIGHT INTO TUE THE UPPER LEVEL STORM SYSTEM WILL MOVE INTO
THE MID MISSISSIPPI VALLEY RGN.  HOWEVER THERE ARE SOME DIFFERENCES
BETWEEN THE ECMWF AND GFS AS THE ECMWF SHOWS A SECONDARY TROUGH
MOVING ACROSS MON NIGHT IN NW FLOW ALOFT ALONG WITH A STG CDFNT
WHICH LEADS TO ANOTHER SHOT OF PCPN MON NIGHT INTO TUE MORNING.
MEANWHILE THE GFS DOES NOT SHOW THIS SECONDARY TROUGH AND HAS MUCH
DRIER AIR OVER THE AREA. FOR NOW WILL JUST MENTION SOME LOW POPS
FOR MON NIGHT BUT KEEP FCST MAINLY DRY FOR TUE. MEANWHILE HIGHS ON
TUE BASED ON THE ECMWF WOULD STAY IN THE 50S WHILE THE GFS HAS
READINGS IN THE 60S. AT THIS TIME WILL TREND WITH THE ECMWF AND
KEEP READINGS IN THE 50S.

&&

.AVIATION...(FOR THE TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1052 AM MDT WED APR 23 2014

CURRENT TAF TRENDS LOOK ON TRACK. WINDS BECOMING MORE NORTHWEST
ACROSS THE AREA WITH SOME GUSTS TO 20 KTS. RADAR DOES SHOW A WEAK
BOUNDARY ACROSS EASTERN ADAMS COUNTY JUST EAST OF DIA. APPEARS TO
BE LOCALIZED BASED ON CURRENT NORTHWEST WINDS ACROSS WELD AND
MORGAN COUNTIES. DO NOT THINK THAT THIS BOUNDARY WILL MOVE ACROSS
DIA WITH THE CURRENT NORTHWEST FLOW. OTHERWISE...THE NORTHWEST
WINDS TO BECOME A BIT MORE NORTHERLY DURING THE AFTERNOON...THEN
EAST TO SOUTHEAST THIS EVENING. SOME HIGH BASED SHOWERS POSSIBLE
THIS AFTERNOON AND EVENING...BEST CHANCE EAST AND SOUTH OF DENVER.
COULD BRIEFLY PRODUCE GUSTY OUTFLOW WINDS ENHANCING THE SURFACE
WINDS. ANY STORMS THAT DEVELOP SHOULD REMAIN WELL EAST OF DENVER
AT THIS TIME...BUT WILL CONTINUE TO MONITOR. VFR CONDITIONS TO
PREVAIL WITH CEILINGS ABOVE 8000 FEET AGL 20Z-02Z. CLEARING SKIES
WITH DRAINAGE WINDS OVERNIGHT.

&&

.FIRE WEATHER...
ISSUED AT 1052 AM MDT WED APR 23 2014

STILL EXPECTING GUSTY WINDS TO AROUND 35 MPH AND RELATIVE
HUMIDITY READINGS IN THE LOWER TEENS WHICH WILL CREATE RED FLAG
CONDITIONS ACROSS SOUTHERN LINCOLN COUNTY THIS AFTERNOON AND EARLY
EVENING. A FEW THUNDERSTORMS WILL BE POSSIBLE LATER THIS AFTERNOON
WHICH COULD BRIEFLY PRODUCE GUSTY OUTFLOW WINDS TO AROUND 45
MPH. THERE IS ALSO A SMALL THREAT OF LIGHTNING WITH THE STORMS. WINDS
TO BECOME NORTHERLY THIS EVENING WITH COOLER AIR AND HIGHER HUMIDITY.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ247.

&&

$$

UPDATE...D-L
SHORT TERM...MEIER
LONG TERM...RPK
AVIATION...D-L
FIRE WEATHER...D-L



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