Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
549 PM CST Tuesday Mar 3 2015

Synopsis...
issued at 329 PM CST Tuesday Mar 3 2015

12z upper air analysis has an 850mb warm front from southwest Iowa into
southern Wisconsin and an upper level disturbance in the plains. A
strong low level jet ran the Rio Grande into the Ohio Valley. Satellite trends
through middle afternoon show plenty of low and middle level clouds across
the Midwest with clearing across the plains.

18z surface analysis had the cold front from near kdlh to ktop with a
pre-frontal trough approaching the Mississippi. Dew points were in the
single digits above and below zero across the northern plains with
30s and high from the middle Mississippi and Ohio valleys into the deep
south.

&&

Short term...(this evening through wednesday)
issued at 329 PM CST Tuesday Mar 3 2015

Quiet and much colder conditions will be seen across the area
tonight and Wednesday as yet another Arctic high builds into the
Midwest. Temperatures will average 20 to 25 degrees below normal.

Long term...(wednesday night through tuesday)
issued at 329 PM CST Tuesday Mar 3 2015

Overview...upper-level pattern will slowly evolve into a split flow
through the week. Polar branch of this flow will bring more Arctic
air into the Midwest as it becomes northwesterly. Large middle to
upper-level ridge will develop over the east Pacific and western U.S.
Into this weekend. The general trend into early next week will be
for the ridge axis to shift into the central U.S. Bringing
moderating temperatures. This forecast period looks mostly dry.

Wednesday night...another Arctic high will move through the plains.
The surface ridge axis will stay west of east Iowa and parallel the
Missouri River valley region which means surface winds will not fully
decouple. Anticipate wind chills between 20 to 25 below along the
I-80 corridor and points north. A Wind Chill Advisory may be needed.

A few sites north of the quadrant cities may approach record lows
especially in areas that received several inches of snow today.
Temperatures will range from the lower single digits near Burlington to
close to -10 f in the north/northwest dvn County Warning Area. Favored Cold Valley locations
will probably be slightly colder.

Thursday and Friday...still cold on Thursday with light winds. Highs in
the lower 20s across the SW with teens elsewhere. 850-500mb flow
becomes zonal which will push 850 mb temperatures to -4 c by Friday afternoon and
1000-500 mb thickness to 540 dam. Should finally see temperatures near or
above freezing across most of east Iowa/west Illinois on Friday.

Saturday through Monday...overall pattern is for dry and warmer
weather. Although a clipper embedded in the northwest flow could bring
light precipitation to the Midwest on sun...the location of which is
uncertain at this time. The Gem is the furthest south with its
solution. Other models are further north and weaker so only
mentioned slight chance for light precipitation for now.

Temperatures are highly dependent on the strength and track of this
clipper. Consensus blend of middle/upper 30s to upper 40s from NE-to-
SW across the dvn County Warning Area is the going forecast with a rather large
amount of uncertainty as east Iowa/west Illinois will be on the
precipice of a building ridge to the W/SW. European model (ecmwf) is pushing for
50s on sun/Mon...GFS is still holding in the 30s to lower 40s.

&&

Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 545 PM CST Tuesday Mar 3 2015

MVFR clouds will gradually clear from west to east
tonight...with VFR conditions thereafter. Expecting an increase in
gustiness this evening with an increasing pressure gradient moving
in from central Iowa...then diminishing slightly after 06z-07z.

&&

Climate...
issued at 329 PM CST Tuesday Mar 3 2015

Record lows for March 5...

Moline.........-13 in 1960
Cedar Rapids...-12 in 1960
Dubuque........-9 in 1978
Burlington.....-13 in 1960

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

Synopsis...08
short term...08
long term...uttech
aviation...rp Kinney
climate...uttech

National Weather Service Glossary of Abbreviations