Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Hastings NE
528 PM CDT Tuesday Mar 11 2014
Short term...(this evening through wednesday)
issued at 331 PM CDT Tuesday Mar 11 2014
Main story through the short term revolving around ongoing
precipitation...which will continue into this evening.
Really no surprises to speak of so far today...with recent radar
imagery showing an area of precipitation getting a little more
organized over western/NC Nebraska...which is starting to creep into north/northwestern
portions of the County Warning Area. Driven by a middle/upper level trough axis
swinging through the plains...and favorable lift via the entrance
region of a 120kt or so upper level jet streak...precipitation
will continue to slides southeast through the rest of the
afternoon/early evening. Expecting the brunt of the activity to
come to an end by middle/late evening...though cant rule out a few
flurries lingering beyond that...and kept the mention going. At
the surface...low pressure continues to trek east across Kansas...with
the main cold front having passed through the County Warning Area earlier this
morning. In came the strong north/northeasterly winds...which have
been in the 25 to 35 miles per hour range sustained...gusts have generally
been in the 40 to 45 miles per hour range...but did have a few gusts getting
over 50 miles per hour. Some locations have fallen below wind advection
criteria...but are close enough for ME to keep the headline going
for now...and let evening crew address in a few hours.
Temperatures as of 3 PM remain well above freezing across the County Warning Area...with
the closest being in the N/NW...but even odx/lxn are in the upper
30s/near 40. Models continue to show 850mb temperatures below
freezing...but if any of that precipitation is going to fall and stick as
snow temperatures would need to start falling. At this point...thinking a
gradual switch over to rain/snow to perhaps all snow in some
locations still possible this evening...but still not looking at
any significant accumulations if it does switch over.
Once this disturbance finally slides off to the east later this
evening...dry conditions return through tomorrow...as sharp
north/northwesterly flow develops in the upper levels in its wake.
An area of high pressure sliding through the region /but mainly
centered near The Rockies/ will result in winds remaining northwest/wrly
as we get into the daytime hours tomorrow /which could be gusty
at times/...and that downsloping component combined with
moderating temperatures aloft brings a rebound in highs. Bumped up highs
a few degrees...have middle 40s in the east and lower 50s in the
Long term...(wednesday night through tuesday)
issued at 331 PM CDT Tuesday Mar 11 2014
Main concerns in the long term will focus on near critical fire
weather conditions on Thursday...chances for precipitation
Saturday into Sunday and high temperatures slightly above normal.
Wednesday night into Thursday...an upper level trough will swing
east of the Central Plains...while an upper level ridge will begin
to dominate most of the western Continental U.S.. a portion of the trough
will remain cut off across the Desert Southwest through much of
As the upper level ridge continues to shift eastward...warmer 850
mb temperatures will also slide east into the region...likely
warming up temperatures nicely for Thursday. Most models indicate
temperatures climbing into the middle 60s...but with strong warm air
advection...see no reason why we cannot get a bit warmer. Aiding
in the warm air advection...strong southerly breezes generated by
a developing surface low along the Front Range of The Rockies will
create near critical fire conditions for Thursday afternoon. Model
guidance suggests sustained winds near 15 to 20 miles per hour.. using the
mixed dewpoint tool...and mixing to at least 850 mb as suggested
by model soundings...went ahead and lowered dewpoints some which
will only aide in lowered relative humidity values. Currently much
of the outlook area will likely be below the 20 percent relative humidity
criteria...but will be marginal on wind speeds.
The cutoff low will become absorbed into the upper level flow by
Friday shifting a cold frontal boundary through the region...while
the upper level ridge slowly retrogrades back westward. As a
result...increased northerly winds are expected by Friday
afternoon. Expect most of the precipitation to remain south of
the region thus leaving Friday dry. Another upper level
disturbance will slide through the area Saturday night into Sunday
which will bring a rain snow mix to the region. Removed chances
for rain across Nebraska by Sunday as the precipitation should be
well to the south...with slight chances across north central
Heading into next week...this secondary disturbance will become a
cutoff low across Mexico...while the upper level ridge finally
begins to shift eastward. Unfortunately...another disturbance
across Canada will help to deamplify the ridge bringing yet
another shot for precipitation to the region on Monday/Tuesday.
Although the models differ in precipitation chances...with the
European model (ecmwf) suggesting more in the way of precipitation than the
GFS...both models indicate the disturbance breaking down the ridge
in the long term.
As for temperatures this week...Thursday will be the warmest day
of the week with highs climbing to the middle 60s. Most days will be
near normal to 5 to 10 degrees warmer. Not expecting any major
cold spells in the near future.
Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 515 PM CDT Tuesday Mar 11 2014
Post frontal precipitation is moving across the area this evening.
Expecting mostly rain for the first hour or two...or through about
0o30z then a gradual mix with then change over to light snow. In
any case...amounts will be light enough visibilities will expected
be reduced below 6 sm. MVFR ceilings will accompany the wave of
precipitation. Expecting the precipitation and lower clouds to last only
for a few hours. Both should have cleared the taf site by 03z.
Finally...strong cross winds will persist on a tight pressure
gradient through 03z. Gusts as high as 35 knots can be expected.
Then the winds will drop off as the pressure gradient relaxes.
Expecting VFR conditions after 03z as strong subsidence builds
over the area. After 14z...the pressure gradient tightens a bit
and northwest winds should gust up to 25 knots.
NE...Wind Advisory until 9 PM CDT this evening for nez039>041-046>049-
Kansas...Wind Advisory until 9 PM CDT this evening for ksz005>007-017>019.