Area forecast discussion
National Weather Service North Platte NE
337 am CDT Friday may 24 2013
Synopsis...
issued at 334 am CDT Friday may 24 2013
At 08z...analysis of the mean sea level data showed low pressure centered in
northwest Colorado and over central Wyoming. From the low in
Colorado...a warm front stretched across southern Colorado to
southwest Kansas and the Texas-Oklahoma Panhandle. Surface dewpoints
in the middle 40s to lower 50s had spread into southwest South Dakota
and western Nebraska. Infra-red satellite imagery showed clouds
streaming across the High Plains on a low level jet of 40-50kt
indicated in the wsr-88 radar wind profilers. The Dodge City
sounding from yesterday evening would indicate precipitable water of
an inch or higher riding in on the low level jet.
&&
Short term...(today and tonight)
issued at 334 am CDT Friday may 24 2013
The warm front lifting northward from southern Colorado will give a
focus for moist air lifting across northeast Colorado and southwest
Nebraska this evening and overnight. With very unstable air (sb-cape
at or above 3000j/kg)... convection is likely to be strong.
However...the deep (0-6km agl) bulk shear over northeast Colorado
will not be real strong (on the order of 35-45kt). Still...since the
storms will move slowly at 10-15kt and low level wind favors
rotation...that may be sufficient for marginally large hail. It
appears though that the greatest risk is heavy rain with organized
convection developing early in the evening and pushing to the
northeast across central Nebraska.
Long term...(saturday through thursday)
issued at 334 am CDT Friday may 24 2013
Saturday continues to look active in terms of convection. Scattered
early morning showers/thunderstorms will be possible...but activity should
be waning in wake of expected Friday night convective complex.
Attention then turns to Saturday afternoon...when additional thunderstorm
activity is possible. At this time it is unclear where the best
potential will exist...this due to expected Friday night storms
likely having an impact on boundaries across the area. The Gem
regional model was preferred over the NAM...as it seems to have a
better handle on the convective activity Friday night. Both models
have a fairly defined warm front Saturday afternoon...the NAM is
focused more across north central Nebraska with the front...while
the Gem regional is farther south...more across southern Nebraska.
Feel the Gem regional farther south scenario is best...as the front
likely will be pushed south some by the Friday night complex. If
convection is less Friday night...then the front may end up somewhat
farther north. Regardless...it will become very unstable near the
boundary by late afternoon...with bulk shear increasing to 40 kts or
greater due to backed east/southeast flow to the north of the front.
GFS indicates a subtle wave ejecting out of the West Coast upper
level low around peak heating/early evening...will give the needed
lift to get thunderstorms going. Models have been fairly consistent the last
few nights with an mesoscale convective system developing across central and eastern
Nebraska...so this is where the highest probability of precipitation will be maintained.
Severe storms possible...with steep middle level lapse rates and
adequate to favorable deep layer shear. Large hail appears to be the
main threat...but a tornado potential may exist just north of the
warm front. Again...later forecasts will better determine where the
front will be located. If surface based storms fail to materialize near
the front...then chances will exist for elevated storms north of the
warm front as a healthy southerly low level jet develops Saturday evening.
Chances for thunderstorms will be nearly daily Sunday through much of next
week...as a large upper level low slowly moves east from the
western Continental U.S. Towards the Central Plains. Difficult to nail down
when and where storms will be...but evening through the overnight
hours will bring the best chance each day. Some severe storms
possible from time to time...but again each days storms will
dictate where the best focus for the next day will be.
Temperature wise...warm period expected...with highs mainly in the
70s and 80s...and lows in the 50s west to 60s east.
&&
Aviation...(for the 06z tafs through 06z Friday night)
issued at 1231 am CDT Friday may 24 2013
Ceilings will lower overnight at both the kvtn and klbf terminals
with ceilings ranging from 800 above ground level in the southwest to 1500 feet above ground level in
northern Nebraska. They will then lift to 3000 to 5000 feet above ground level by
Friday afternoon. For the klbf terminal...thunderstorms are
possible Friday evening...with the greatest chance after 02z
Saturday. At this time...our confidence is not high that they will
occur at the lbf terminal. However...they are likely to be in the
area. Winds over the next 24 hours will be from the southeast and
south at 10 to 20 kts for the remainder of tonight...increasing to
20 to 30 kts on Friday. Some wind gusts of 25 to 45 kts are
possible in the vicinity of thunderstorms Friday evening at the
klbf terminal.
&&
Lbf watches/warnings/advisories...
none.
&&
$$
Synopsis...Springer
short term...Springer
long term...Taylor
aviation...Springer
