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FXUS63 KTOP 051136 AAA
AFDTOP

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TOPEKA KS
536 AM CST Thu Mar 5 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 256 AM CST THU MAR 5 2015

Water vapor imagery at 0815Z confirming dry air and subsidence
across the county warning area that models are all showing will
persist through today. Cold surface high pressure ridge remains in
control with low temps this morning expected to be about 20
degrees below normal for early March. Although the ridge will
retreat to the east and winds will veer around to the south in the
afternoon with abundant sunshine...highs today will commonly be 15
degrees below average. Highs should range from near the freezing
mark at Hiawatha to near 40 in the Minneapolis vicinity.

For tonight...the combination of a few mid and high clouds and a
persistent southerly wind should help to limit low temps to the low
to middle 20s.

.LONG TERM...(Friday through Wednesday)
Issued at 256 AM CST THU MAR 5 2015

Northwest flow remains the predominant feature of the weather
pattern for the weekend and next week. Models continue to show
little if any low level moisture return while keeping any weak
perturbation within the flow mainly north of the forecast area.
because of this there is little reason to deviate from a dry
forecast.

The warming trend also looks on track and have only made minor
adjustments to the previous forecast. There remains indications of
a weak Pacific frontal boundary moving into the area this weekend
while weakening. For now there does not appear to be much in the
way of cold air associated with this boundary as models show only
very weak cold air advection. With this in mind and expecting
decent insolation to offset the weak wind shift, think highs are
still likely to be above normal. The strongest warm up is expected
to occur on Tuesday and Wednesday as models strengthen the thermal
ridge to the west of the forecast area. With model progs of 925 MB
temps around 15C, we could push the 70 degree mark in some
locations.

Uncertainty increases just beyond the forecast period as the GFS
and ECMWF show some divergence in their solutions of the synoptic
pattern. The GFS is stronger with energy digging southeast from AK
for the second half of the work week. This causes a Canadian
airmass to move south through the plains. Meanwhile the ECMWF is
almost the complete opposite of the GFS. This will be something to
watch in later runs of the models.

&&

.AVIATION...(For the 12Z TAFs through 12Z Friday Morning)
Issued at 530 AM CST THU MAR 5 2015

Terminals will remain VFR through the forecast period with only
a few mid and high clouds. Light east to northeasterly winds will
slowly veer to the southeast by 19z at speeds of 6-9 kts....then
persist for the remainder of the forecast period.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...63
LONG TERM...Wolters
AVIATION...63