Severe Thunderstorm Warning 6, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
315 PM MDT SAT MAY 18 2001

SHORT TERM DISCUSSION:  UPR LVL DISTURBANCE IS STILL OVR NRN UT THIS
AFTN...PROGREESING EWD.  LIGHTNING DATA SHOWS STRIKES OVR UT AND A
FEW HITS OVR THE NW MTNS.  THE EVENING CONVECTION SEEMS LIKE IT WILL
ONLY HOLD TOGETHER OVER THE MTNS.  DEWPTS ALG THE I-25 CORRIDOR HAVE
DROPPED TO THE LOW 30S AND WSR-88D SHOWS SHOWERS DISSIPATING AS THEY
MOVE AWAY FROM THE FTHLS.  IT APPRS THAT THE REST OF THE PLAINS
SHOULD NOT SEE ANY SHOWERS SINCE THE DAYLIGHT HEATING WILL BE ENDING
BEFORE THE CONVECTIVE INHIBITION IS OVERCOME.  ACARS SOUNDINGS SHOW
A STRONG INVERSIONS STILL IN PLACE ABOVE 500 MB.  AFTER MIDNIGHT THE
UPR LVL DISTURBANCE WL BE MOVG OVERHEAD AS A SFC FRONT DROPS SWD OVR
THE PLAINS.  THE UPSLOPE FLOW SHOULD COMBINE WITH DYNAMIC FORCING
ALOFT FOR SCT SHOWER ACTIVITY.                             KDRBY

LONG TERM DISCUSSION:  SHORT WAVE WILL MOVE SLOWLY EAST/SOUTHEAST
ACROSS THE CWA ON SATURDAY...BRINGING MORE UNSETTLED WEATHER TO THE
AREA.  THIS SYSTEM LOOKS VERY SIMILAR TO THE ONE THAT CAME THROUGH
YESTERDAY ALTHOUGH UPSLOPE AND DYNAMICS ARE SLIGHTLY WEAKER.
HOWEVER...WE STILL COME UNDER THE INFLUENCE OF WEAK Q-G FORCING AND
RIGHT ENTRANCE REGION OF JET MAX.  SCATTERED SHOWERS AND A FEW
THUNDERSTORMS LOOK GOOD...BUT WILL HAVE LIKELY POPS OVER THE
SOUTHERN PORTION OF THE CWA WHERE BEST MOISTURE AND INSTABILITY
EXIST.  THEN WE RAPIDLY DRY SATURDAY NIGHT WITH TROF AXIS PASSAGE.

NEXT SYSTEM IS THE ONE TO WATCH AS MODELS HAVE BEEN HAVING A TOUGH
TIME HANDLING MOVEMENT OF UPPER AIR FEATURES.  12Z RUNS HAVE AGAIN
REVERTED TO YESTERDAYS 12Z RUNS OF MUCH COLDER AND DEEPER WITH THE
TROF.  CANT SEE MUCH REASON TO ARGUE WITH THE DEEPER ETA WITH AMOUNT
OF UPPER RIDGING OVER THE GULF OF ALASKA AND STRENGTH OF JET MAX
TOPPING THE RIDGE...AND SURFACE TEMPS IN THE 20S IN THE SOURCE
REGION.  ETA EXTENDED LOOKS DANGEROUS WITH 540 THICKNESS AND BETWEEN
0.5 AND 1 INCH OF PRECIP ON THE PLAINS.  WILL HAVE TO WATCH THIS
SYSTEM CAREFULLY.

THEN BACK TO RIDGING AND MUCH WARMER TEMPS NEXT WEEK.  SOME MOISTURE
WILL PROBABLY MANIFEST ITSELF UNDER THE RIDGE TO WARRANT A FEW
THUNDERSTORMS IN/NEAR THE MOUNTAINS BY MID WEEK.

BARJENBRUCH

.DEN...NONE.