Area Forecast Discussion
Issued by NWS Amarillo, TX

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KAMA 142328
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
528 PM CST Sat Jan 14 2017

.DISCUSSION...

Approaching major storm system across baja is providing over-
running sw flow above extremely shallow but cold airmass at the sfc.
Temps are still below freezing fall all but far w and sw zones this
aftn. Extreme moisture with isentropic upglide and upr diffluence in
advance of the mid-upr low are producing widespread rain and freezing
rain across the area. There are some embedded elevated thunderstorms
in unstable air above an insane warm nose where temps are near 10 deg
c. As expected the rain is not supercooled given the shallow layer of
freezing temps and therefore we are not seeing a textbook...freeze on
contact...type freezing rain event. Luckily this will continue to be
a mitigating factor that allows only a small percentage of the total
rainfall to freeze mainly on elevated surfaces which is why we
continue to limit ice accumulations to 1/2" in the warning area. Not
sure even the warning area will see these ice totals...but will let
advisories ride as is for now as darkness may allow a bit more
efficient freezing process overnight. Lows tonight will not drop much
below current readings.

When all said and done...the main story from all this may be the
amount of rain we will see through sunday. Isentropic upglide is
impressive to say the least as srly flow just above the shallow cold
airmass increases through sunday as the upper low approaches.
Strongly diffluent flow aloft and strong q-vector convergence will
aid in massive large scale lift on sunday as storm moves towards the
area. Pops are pretty much in categorical range for most of the area
and flat out showed 100% for cen zones on sunday. Elevated tstms will
provide heavy rainfall and small hail as everything coming to a head
on sunday afternoon. Storm total rainfall amounts 2" are expected and
some localized flooding is possible on sunday. The warm nose is
slowly trying to erode the near sfc cold wedge...but hard to say
exactly how far into sunday we will remain below freezing but 18z
still seems like good end time for current winter products. Like
cooler raw blends best for temps sunday which means most areas should
rise above freezing but remain below 40.

Model trends on the track of the low take it directly across the
central or se panhandle now sunday night. GFS is the only model not
showing 0 to -3 deg c h85 temps wrapping around nw side and into the
region quickly after 00z monday and is therefore the only model not
suggesting a change over to sleet and snow for at least the nw half
of the panhandle sunday night. We are leaning toward a
GEM...ECMWF...NAM12 compromise and are showing 1-4" of snow across
the NW Panhandles sunday night. There is some concern for higher
amounts as we will be in the sweet spot of the low which could lead
to some heavy snow at times unless the GFS verifies the warmer h85
temp profiles. TTU WRF also shows significant snow bands in the
region by midnight and we will have to continue to monitor for
possibility of higher snow amounts in the area. We are showing
highest snow totals in the far nw...but this portion of the forecast
is the most dependent on exact storm track...so stay tuned. Temps
show warm to near 40 north and low 50s se so snow will begin melting
quickly monday aftn.

After this weekend (target of opportunity) didn`t deviate much from
superblend. There is some uncertainty wrt another s/wv dropping
across the plains on tue but kept things dry for now with temps
rising above normal. Things could get interesting next weekend again
as models show a closed low moving very near the panhandles again. Latest
ecmwf and gfs take this system just north but there are GFS ensembles
showing a further south track. If srn track pans out could see next
rain then snow chc with this system Sat/Sun. Kept POPS at 20 for now
given uncertainty.

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                31  36  31  45  27 /  90 100  80  20   5
Beaver OK                  29  33  30  40  25 / 100 100 100  40   5
Boise City OK              29  33  27  39  24 /  90 100 100  40   5
Borger TX                  31  35  31  44  29 /  90 100  90  20   5
Boys Ranch TX              32  36  30  45  26 / 100 100  80  20   5
Canyon TX                  32  36  31  47  27 /  90 100  70  20   5
Clarendon TX               31  37  33  50  29 /  70 100  90  10   5
Dalhart TX                 31  34  28  42  25 /  90 100  80  30   5
Guymon OK                  29  33  29  40  25 / 100 100 100  40   5
Hereford TX                33  37  30  47  26 /  90 100  70  10   5
Lipscomb TX                30  34  31  42  27 /  90 100 100  30   5
Pampa TX                   31  35  31  43  27 /  80 100 100  20   5
Shamrock TX                31  37  33  48  29 /  70 100 100  10   5
Wellington TX              31  39  35  52  30 /  60 100 100  10   5

&&

.AMA Watches/Warnings/Advisories...
TX...Ice Storm Warning until noon CST Sunday for the following zones:
     Hemphill...Lipscomb...Ochiltree...Roberts...Wheeler.

     Freezing Rain Advisory until noon CST Sunday for the following
     zones: Armstrong...Carson...Collingsworth...Dallam...
     Donley...Gray...Hansford...Hartley...Hutchinson...Moore...
     Oldham...Potter...Randall...Sherman.

OK...Ice Storm Warning until noon CST Sunday for the following zones:
     Beaver...Texas.

     Freezing Rain Advisory until noon CST Sunday for the following
     zones: Cimarron.


&&

$$

88/1


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.