000
FXUS65 KBOU 191721
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1121 AM MDT SUN MAY 19 2013

.UPDATE...

&&

.SHORT TERM...CIRCULATION AROUND THE UPPER LOW CENTERED OVER
SOUTH CENTRAL NEBRASKA CONTINUES TO FEED MOISTURE BACK ACROSS THE
NORTHEAST CORNER OF THE STATE THIS MORNING. THE RESULT HAS BEEN
NUMEROUS RAIN SHOWERS AND SCATTERED THUNDERSTORMS FOR LOGAN...
NORTHERN WASHINGTON...PHILLIPS AND SEDGWICK COUNTIES.
PRECIPITATION AMOUNTS REMAIN LOW AS PER RADAR QPF ALGORITHMS...BUT
ENOUGH TO CERTAINLY WET THE GROUND IN MANY AREAS. STORMS IN THE
PAST COUPLE OF HOURS HAVE ALSO GENERATED A FAIR NUMBER OF CG
LIGHTNING STRIKES IN THIS AREA. ELSEWHERE...PRECIPITATION HAS BEEN
SPOTTY AND LIGHT... EVEN IN THE HIGH COUNTRY. WIDESPREAD CLOUD
COVER...COOLER TEMPERATURES AND STABLE LAPSE RATES ARE TO BLAME
FOR THE LESS THAN EXPECTED SHOWER ACTIVITY BEYOND THE NORTHEAST
CORNER COUNTIES. NORTHWEST FLOW HAS ALSO RESULTED IN CONSIDERABLY
LESS CLOUD COVER ALONG THE LEESLOPE OF THE FRONT RANGE. FOR THESE
REASONS...HAVE REDUCED CLOUD COVERAGE ALONG THE FRONT RANGE FOR
TODAY AND LOWERED POPS IN THIS AREA TO ISOLATED FOR THIS
AFTERNOON. HAVE ALSO LOWERED POPS IN THE HIGH COUNTRY BUT KEPT THE
CHANCE OF SNOW SHOWERS FOR ELEVATIONS GENERALLY ABOVE 10 THOUSAND
FEET. NOT EXPECTING ANY APPRECIABLE ACCUMULATION UNTIL LATER
TONIGHT. ALSO MADE MINOR ADJUSTMENTS TO TODAY/S TEMPERATURES AND
WINDS.

.AVIATION...VFR CONDITIONS ANTICIPATED AT DENVER AREA AIRPORTS
NEXT 24 HOURS. A DRY NORTHWEST FLOW OFF THE GROUND SHOULD LIMIT
THE FORMATION OF PRECIP PRODUCING CLOUDS IN THE DENVER AREA
THROUGH THIS EVENING. TOWARD MORNING...THERE WILL BE A SLIGHTLY
BETTER CHANCE OF LIGHT RAIN SHOWERS WITH A WEAK UPPER LEVEL
WEATHER DISTURBANCE PASSING OVERHEAD. SOUTH-SOUTHWEST WINDS OF
6-13KTS ARE EXPECTED TO BECOME WEST-NORTHWEST IN THE AFTERNOON AT
SPEEDS OF 7-13KTS AND REMAIN THERE THROUGH EARLY THIS EVENING.
THEN BACK TO A SOUTH TO SOUTHWEST WIND OF 4-9KTS.

&&

.HYDROLOGY...NO CONCERNS AT THIS TIME.

&&

.PREV DISCUSSION... /ISSUED 442 AM MDT SUN MAY 19 2013/

SHORT TERM...UPPER TROUGH CONTINUES TO MOVE SLOWLY EAST WITH
COOLER AND SLIGHTLY UNSTABLE AIR OVER COLORADO. NOT A LOT OF
SHOWER ACTIVITY AT THIS TIME...BUT WILL INCREASE WITH DAYTIME
HEATING. LIFT SHOULD BE GREATEST IN AREAS NORTH OF DENVER THROUGH
THE PERIOD. MOISTURE LIMITED AND SHOWERS EXPECTED TO BE FAIRLY
DISORGANIZED...SO NOT EXPECTING SIGNIFICANT RAINFALL AMOUNTS BUT I
DID RAISE THE POPS EXPECTING DECENT COVERAGE THIS AFTERNOON. AS
NORTHERLY WINDS INCREASE THERE WILL BE SOME OROGRAPHIC ENHANCEMENT
OF THE PRECIPITATION IN THE NORTHERN MOUNTAINS TONIGHT...AND THE
SNOW LEVEL WILL LIKELY BE IN THE 8-9 THOUSAND FOOT RANGE...SO WE
COULD WIND UP WITH SOME DECENT ACCUMULATIONS IN THE HIGH MOUNTAINS
OF LARIMER AND JACKSON COUNTIES. ON THE PLAINS SHOWERS SHOULD
DECREASE WITH THE LOSS OF HEATING...BUT THERE WILL STILL LIKELY BE
SOME SHOWERS AROUND. BETWEEN THE N-NW BREEZE AND TEMPERATURES
ABOUT 20 DEGREES LESS THAN YESTERDAY...IT WILL FEEL COOL EVEN
THOUGH TEMPERATURES WILL REALLY BE NEAR THE NORMALS FOR THIS DATE.
WINTER...THEN SUMMER...NOW WE GET SPRING.

LONG TERM...MODELS HAVE AN UPPER CLOSED LOW OVER THE BORDER AREA
OF CENTRAL NEBRASKA AND CENTRAL SOUTH DAKOTA AT THE START OF
MONDAY. AN UPPER TROUGH IS STRETCHED FROM THE LOW
SOUTHWESTWARD INTO THE FOUR CORNERS. THE UPPER LOW MOVES
LITTLE...WITH THE UPPER TROUGH AXIS MOVING SLOWLY EASTWARD TO THE
COLORADO EASTERN BORDER BY 06Z MONDAY NIGHT. THE FLOW ALOFT IS
WEAK AND NORTH OR NORTHEASTERLY MONDAY AND MONDAY NIGHT. THROUGH
THE DAY TUESDAY...IT BECOMES NORTHWESTERLY. SAME FOR TUESDAY
NIGHT...BUT SPEEDS STAY FAIRLY WEAK. WEAK UPWARD VERTICAL MOTION
IS PROGGED FOR THE CWA MONDAY INTO MONDAY EVENING...THEN WEAK
DOWNWARD SYNOPTIC SCALE ENERGY IS PROGGED THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER FLOW IS PROGGED TO BE ALL NORTHWESTERLY
DOWNSLOPING FOR THE CWA MONDAY THROUGH MUCH OF TUESDAY...BEFORE
WEAK NORTHEASTERLIES ARE PROGGED THE REST OF TUESDAY AND TUESDAY
NIGHT. FOR MOISTURE...THE MODELS SHOW IT TO BE WIDESPREAD AND DEEP
MONDAY AND MONDAY EVENING...THEN A DECREASE AFTER MIDNIGHT. THERE
IS STILL SOME AROUND TUESDAY...WITH DECENT DRYING TUESDAY NIGHT.
THERE IS VERY LITTLE CAPE PROGGED ON MONDAY OR MONDAY EVENING.
THERE IS A TAD MORE PROGGED FOR LATE DAY TUESDAY...BUT NOTHING
MUCH ABOVE 200 G/KG AND THAT IS FOR THE WESTERN HALF OF THE CWA.
THE QPF FIELDS SHOW FAIRLY DECENT PRECIPITATION AMOUNTS MONDAY
INTO MONDAY EVENING. THEY CERTAINLY SHOW MORE FOR MONDAY THAN
YESTERDAY`S 00Z RUNS. THERE IS LESS INDICATED FOR TUESDAY...BUT
STILL THERE IS SOME. FOR POPS...BEST MONDAY AND MONDAY EVENING
..WITH 30-60%S FOR ALL THE CWA. SOME LINGERING MONDAY NIGHT...
THEN 20-30% IN THE HIGH COUNTY AND NORTHEAST CORNER LATE DAY
TUESDAY. LITTLE TO NONE FOR THE FOOTHILLS AND WESTERN PLAINS...
TOO DRY AND DOWNSLOPING. FOR TEMPERATURES...MONDAY`S HIGHS WILL BE
1-3 C COOLER THAN TODAY`S. TUESDAY`S HIGHS CLIMB 2-5 C FROM
MONDAY`S. FOR THE LATER DAYS...WEDNESDAY THROUGH SATURDAY...THERE
IS UPPER RIDGING WEDNESDAY AND THURSDAY...THEN SOUTHWESTERLY FLOW
ALOFT FOR FRIDAY AND SATURDAY. THERE IS LIMITED MOISTURE AND
WARMING TEMPERATURES.

AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS EXPECTED THIS AFTERNOON. THERE IS
A CHANCE THAT CEILINGS COULD DROP LOW ENOUGH TO REQUIRE INSTRUMENT
APPROACHES TO KDEN IN THE AFTERNOON AND EARLY EVENING. NORTHERLY
WINDS WILL GUST IN THE 20-30 KNOT RANGE AT TIMES...MAINLY DUE TO
MIXING OF THE WINDS ALOFT...BUT POSSIBLY ENHANCED BY SHOWERS.

HYDROLOGY...RAIN SHOWERS ARE EXPECTED TO BE TOO LIGHT TO CAUSE
FLOODING.

&&

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

$$

SHORT TERM...BAKER/GIMMESTAD
LONG TERM....RJK
AVIATION...BAKER/GIMMESTAD