Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 031727
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1127 AM CST Tue Mar 3 2015
...18Z Aviation Update...
.SHORT TERM...(Today through Wednesday night)
Issued at 240 AM CST TUE MAR 3 2015
For today, may see some early morning drizzle associated with the
strong warm advection ongoing across the area. A shortwave and
associated cold front will begin to push into the area later today
with rain shower chances increasing...especially over the eastern
CWA. Not particularly looking for much in the way of measured
rainfall with best moisture transport to our east. Previous shift
had removed thunder from the forecast due to a lack of instability
and this still looks good. Highs today should reach the low to mid
50s across the area with the lower readings where the front will
go through the earliest in west central MO.
Tonight is when the transition will begin. A cold air mass will
force a cold front through the entire area during the evening,
with temperatures eventually dropping below the freezing mark from
around 11 pm onward from northwest to southeast. Precipitation
will begin to expand overnight as upper level energy moves towards
the area from the northwest and a very strong upper level jet
intensifies. Initially a warm layer above freezing (800-700mb)
will be in place over the southeastern half of the CWA, but this
will be eroded in time as cold air moves in from the northwest. So
there may be an initial period of rain changing to freezing rain
then sleet and eventually snow along and south of I-44.
This transition line should push totally south of the area by late
morning Wednesday with all snow expected after that point. Models
continue to show drastic differences in the QPF fields with the
NAM remaining the most aggressive. All are showing pretty
substantial lifting from late tonight through Wednesday, and while
the NAM may be a significant outlier, I don`t want to completely
rule it out at this point. All are expecting the highest
probability of accumulating snowfall along and southeast of the
I-44 corridor which is what we have been advertising and will
continue to do so. Still have lower confidence in specific amounts
at this time due to continued model differences, but given the
intensity of the dynamics, would not be surprised to see amounts
move towards what the NAM is suggesting. Fly in ointment for this
time of year will be the higher sun angle we start seeing in March
and daytime snowfall is harder to accumulate because of this.
For now we are going with a half inch to inch in our northwestern
CWA...to 1-3 inches along the I-44 corridor...and a 3-6 inch
amount over south central MO. For ice...we are going with a
glazing to around 0.05 hundredths along and south of the I-44 corridor.
NAM holds on to snowfall through Wednesday night and the new ECMWF
to a lesser degree does as well. Have extended our snow chances
into Wednesday night because of this.
Leaning towards no headlines at this point and wait for one more
model run before making that decision.
.LONG TERM...(Thursday through Monday)
Issued at 240 AM CST TUE MAR 3 2015
Everything should clear out by Thursday morning with a very cold
air mass moving into the area. The surface ridge will be directly
overhead Thursday and begin to shift to the east by Thursday
night. Coldest temperatures are expected in those locations
impacted by the snowfall and we have single digits going there
both Wednesday night and Thursday night and could see some wind
chills dip below zero.
Remainder of forecast looks dry at this point and we should see a
pattern change after the cold air shifts to the east. We should
have a moderating trend beginning late in the week and continuing
into next week.
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1123 AM CST TUE MAR 3 2015
IFR conditions will be the rule this afternoon, with gusty
southwest winds expected ahead of an approaching front. Exact
timing of the front will be a challenge, but mid evening looks to
be the rule for now.
As that front passes, expect a period of gusty north winds. In
addition, areas of rain will develop across the region, with a
transition to freezing rain and then a mix of sleet, snow, and
freezing rain as temperatures cool. A change to all snow is then
expected tomorrow; that change should occur during the mid morning
hours for SGF and JLN, and late morning or early afternoon for
BBG. Again, exact timing is a challenge. Once the change to all
snow takes place, expected widespread IFR or LIFR vis.
MO...WINTER STORM WATCH from Wednesday morning through late Wednesday
night FOR MOZ082-083-092-096>098-104>106.