Severe Thunderstorm Warning 18, NWS Pueblo, CO

SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO COLORADO
147 PM MDT SUN MAY 20 2001

MAIN FORECAST CONCERN WILL BE COLD FRONT QUICKLY MOVING THROUGH THE
CWA LATE THIS AFTN AND EVE...WITH STORMS AHEAD OF IT...AND SNOW
CHANCES BEHIND.

CURRENTLY: MOSTLY SUNNY TO PARTLY CLOUDY SKIES ACROSS THE CWA AS PER
VISIBLE SATELLITE IMAGERY. SFC OBS INDICATE MILD TEMPS AND SOMEWHAT
LIGHT WINDS ACROSS PUB CWA...WHILE STRONG NORTHERLY FLOW AND
DROPPING TEMPS REVEAL COLD FRONT TO BE ALONG THE CO/WY BORDER AND
ACROSS EXTREME NE CO. 500 MB ANALYSIS SHOWS UPPER LOW DROPPING DOWN
INTO THE DAS...WITH THE 120 KT DRIVING IT EDGING DOWN INTO THE N
ROCKIES. SHORT TERM MODELS ARE SOMEWHAT SIMILAR...BUT ETA WENT A
LITTLE STRONGER WITH THE FRONT COMING THROUGH TONIGHT. NGM AGREES...
SO WILL GO WITH ETA.

TONIGHT: LOW CLOUDS AND SNOW SHOWERS ARE ALREADY OCCURRING IN
WYOMING...SO THE COLD AIR IS COMING. OVERLAY OF 850 WINDS AND TEMPS
INDICATE THAT MAIN BRUNT OF COLD AIR WILL BE AT THE PALMER DIVIDE
AT 00Z...THEN BARREL THROUGH E CO SOMETIME BETWEEN 6PM AND MIDNIGHT.
SO...TWO SITUATIONS ARE IN QUESTION HERE...BEFORE AND AFTER FRONT.
FIRST...LAPSE RATES AHEAD OF THE FRONT ARE AROUND 8...WHILE ALOFT
FAVORABLE DIV Q MOVES ACROSS THE REGION. THEREFORE DYNAMICS/UPWARD
MOTION IS IN PLACE...AND FRONT WILL BE MOVING SO FAST THAT BY SHEER
BRUTE FORCE LOWER ATMOSPHERE WILL BE IN TURMOIL. SOMEWHAT LACKING
INGREDIENT THOUGH WILL BE ABUNDANT MOISTURE. THERE IS SOME LOW
LEVEL MOISTURE ACROSS THE E PLAINS...BUT NOT TOO IMPRESSIVE. I FULLY
EXPECT THUNDERSTORMS AND SHOWERS TO DEVELOP AHEAD AND ALONG THE
FRONT THIS EVENING...BUT QUESTION SEVERITY. SECOND...SHOWERS WILL
DEVELOP ALONG THE FRONT AND ARE EXPECTED TO CONTINUE THROUGH EARLY
MONDAY MORNING. HOWEVER...AS THE COLD AIR MOVES IN...RAIN WILL
CHANGE TO SNOW ACROSS THE HIGHER ELEVATIONS (MTS AND PALMER
DIVIDE)...AND MIX WITH SNOW ELSEWHERE. NOT INCLINED TO ISSUE ANY
ADVISORIES AT THIS TIME BECAUSE OF THE WARM GROUND AND SPEEDINESS
OF FRONT. ONGOING FORECAST HAS 2-4 INCHES ON GRASSY AREAS FOR THE
HIGHER TERRAIN...AND 2-3 INCHES ON GRASSY AREAS FOR N EL PASO
COUNTY. THIS SOUNDS GOOD AND WILL CONTINUE STRONG WORDING IN ZONES.
ANOTHER INGREDIENT WILL BE THE WINDS. EXPECTING NORTH WINDS AT 25-
35 MPH TONIGHT...WITH GUSTS UP TO 50 MPH POSSIBLE. WINDS SHOULD STAY
RIGHT BELOW WARNING CRITERIA...SO WILL MAINTAIN STRONG ZONE WORDING.

MONDAY AND MONDAY NIGHT: EXCEPT FOR SOME POSSIBLE LINGERING SHOWERS
ACROSS THE E PLAINS EARLY MONDAY MORNING...EXPECT MONDAY TO BE
MAINLY PARTLY CLOUDY AND COOLER DUE TO COLD AIR SCOURING OUT THE
REGION. TEMPS AT BOTH 850 AND 700 MB COOL BY 11-13 DEG C AS
COMPARED TO SUNDAY READINGS...SO BIG COOL-DOWN IN PLACE AT LEAST FOR
THE DAY. DEEP COLD-POOL AND UPPER DYNAMICS CONTINUE TO THE E-SE OUT
OF THE AREA...AND BY MONDAY EVENING PARTLY CLOUDY SKIES WITH NW
FLOW ALOFT WILL BE IN PLACE. MONDAY NIGHT SHOULD BE A VERY COLD
NIGHT...AND INCOMING SHIFT MAY HAVE TO LOOK AT POSSIBLY A FREEZE
ADVISORY FOR MON NIGHT/TUES MORNING...ESPECIALLY FOR THE SAN LUIS
VALLEY. WILL WAIT FOR NOW TO SEE IF CURRENT COLD FRONT BEHAVES AS
IS EXPECTED.

TUESDAY AND TUESDAY NIGHT: HIGH PRESSURE RIDGE BUILDS INTO THE SW
US...WITH CO UNDER A NW FLOW ALOFT. SLOW AND STEADY WARMING AS
TEMPS BEGIN TO REBOUND.

FOR THE EXTENDED (WED THROUGH SUN): CONTINUED MILD AND TRANQUIL
WEATHER EXPECTED FOR THE REMAINDER OF THE PERIOD...WITH HIGH PRES
RIDGE IN PLACE OVER THE SW US. MAJORITY OF MOISTURE AND DYNAMICS
REMAINS TO THE NORTH AND EAST OF COLORADO...WITH NW-W FLOW ALOFT.
WILL JUST ADD SUNDAY TO THE OUT-PERIOD.
h
.PUB...NONE.

MOORE

COZ058>081-201910-

SIGNIFICANT WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PUEBLO CO
1159 AM MDT SUN MAY 20 2001

...BIG CHANGE IN THE WEATHER COMING TO SOUTHERN COLORADO...

A STRONG COLD FRONT WILL BLAST ACROSS SOUTHEAST COLORADO THIS
EVENING BRINGING RAPIDLY FALLING TEMPERATURES...WIND GUSTS OVER 45
MPH AND SNOW SHOWERS.

THE COLD FRONT MOVED THROUGH FORT COLLINS AROUND 330 PM. WHEN IT
WENT THROUGH THE WIND GUSTS JUMPED TO 50 MPH AND THE TEMPERATURE
DROPPED 20 DEGREES IN 30 MINUTES.

THE COLD FRONT WILL CROSS MONUMENT RIDGE BETWEEN 530 PM AND 600 PM
THEN MOVE QUICKLY SOUTH ACROSS COLORADO SPRINGS AROUND 600 PM THEN
TO PUEBLO AND LA JUNTA AROUND 700 PM.

BEHIND THE COLD FRONT TEMPERATURES WILL FALL RAPIDLY WITH SNOW AND
BLOWING SNOW DEVELOPING OVER A LARGE AREA. SNOW ACCUMULATIONS WILL
BE 2 TO 4 INCHES OVERNIGHT ALONG THE PALMER DIVIDE AND IN TELLER
COUNTY AND POSSIBLY AND INCH OR TWO IN THE COLORADO SPRINGS AREA.
MOST OF THE ACCUMULATIONS WILL BE ON GRASSY SURFACES WITH ROADS
REMAINING WARM ENOUGH TO MELT THE SNOW. IN PUEBLO AND LA JUNTA THE
PRECIPITATION WILL BE RAIN MIXED WITH SNOW.

TEMPERATURES TONIGHT WILL PLUMMET AFTER THE FRONT GOES BY. THE MOST
DRAMATIC DECREASE IN TEMPERATURES WILL OCCUR ACROSS THE PLAINS AND
THE SOUTHERN MOUNTAINS...INCLUDING PIKES PEAK...THE WET MOUNTAINS...
AND THE SANGRE DE CRISTO MOUNTAINS. TEMPERATURES ON THE PLAINS WILL
BE IN THE 30S BY MORNING...AND IN THE 20S IN THE MOUNTAINS.

PLEASE STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE MEDIA FOR
LATER UPDATES REGARDING THIS STRONG WEATHER SYSTEM MOVING ACROSS
COLORADO.

COZ058>081-202330-

SIGNIFICANT WEATHER OUTLOOK...CORRECTION TO EXPIRE TIME
NATIONAL WEATHER SERVICE PUEBLO CO
1159 AM MDT SUN MAY 20 2001

...BIG CHANGE IN THE WEATHER COMING TO SOUTHERN COLORADO...

A STRONG COLD FRONT WILL BLAST ACROSS SOUTHEAST COLORADO THIS
EVENING BRINGING RAPIDLY FALLING TEMPERATURES...WIND GUSTS OVER 45
MPH AND SNOW SHOWERS.

THE COLD FRONT MOVED THROUGH FORT COLLINS AROUND 330 PM. WHEN IT
WENT THROUGH THE WIND GUSTS JUMPED TO 50 MPH AND THE TEMPERATURE
DROPPED 20 DEGREES IN 30 MINUTES.

THE COLD FRONT WILL CROSS MONUMENT RIDGE BETWEEN 530 PM AND 600 PM
THEN MOVE QUICKLY SOUTH ACROSS COLORADO SPRINGS AROUND 600 PM THEN
TO PUEBLO AND LA JUNTA AROUND 700 PM.

BEHIND THE COLD FRONT TEMPERATURES WILL FALL RAPIDLY WITH SNOW AND
BLOWING SNOW DEVELOPING OVER A LARGE AREA. SNOW ACCUMULATIONS WILL
BE 2 TO 4 INCHES OVERNIGHT ALONG THE PALMER DIVIDE AND IN TELLER
COUNTY AND POSSIBLY AND INCH OR TWO IN THE COLORADO SPRINGS AREA.
MOST OF THE ACCUMULATIONS WILL BE ON GRASSY SURFACES WITH ROADS
REMAINING WARM ENOUGH TO MELT THE SNOW. IN PUEBLO AND LA JUNTA THE
PRECIPITATION WILL BE RAIN MIXED WITH SNOW.

TEMPERATURES TONIGHT WILL PLUMMET AFTER THE FRONT GOES BY. THE MOST
DRAMATIC DECREASE IN TEMPERATURES WILL OCCUR ACROSS THE PLAINS AND
THE SOUTHERN MOUNTAINS...INCLUDING PIKES PEAK...THE WET MOUNTAINS...
AND THE SANGRE DE CRISTO MOUNTAINS. TEMPERATURES ON THE PLAINS WILL
BE IN THE 30S BY MORNING...AND IN THE 20S IN THE MOUNTAINS.

PLEASE STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE MEDIA FOR
LATER UPDATES REGARDING THIS STRONG WEATHER SYSTEM MOVING ACROSS
COLORADO.