Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 310343
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
1043 PM CDT MON MAY 30 2016

.Aviation...
An upper trough moving into the Panhandles tonight will allow for
isolated convection to possibly affect the Amarillo TAF site between
06Z and 10Z Tuesday. A cold front will push into the Panhandles
tonight...moving across the Dalhart and Guymon TAF sites around 09Z
to 11Z Tuesday and then across the Amarillo TAF site around 14Z to
16Z Tuesday. Winds will back from the southeast to the east and
northeast following the passage of the cold front 10 to 20 knots and
then diminishing to 5 to 15 knots and backing to the northeast and
north 5 to 15 knots after 20Z to 22Z Tuesday. Convection expected to
develop after 20Z to 22Z Tuesday across mainly the central
Panhandles...so included PROB30 group in the Amarillo and Guymon TAF
sites after 20Z Tuesday. VFR conditions should become MVFR to IFR and
possibly even LIFR after 16Z to 20Z Tuesday at the Amarillo and
Dalhart TAF sites...and at the Guymon TAF site after 06Z to 10Z
Tuesday.

Schneider

&&

.Prev Discussion... /Issued 639 PM CDT MON MAY 30 2016/

Aviation...
00Z TAF Cycle

An upper trough will move across the Panhandles tonight which could
allow for some isolated convection to push east out of the southern
Rockies and across the northern and western Panhandles through about
03Z to 06Z Tuesday. Confidence low and will leave out of TAF forecast
package for now but update if needed. Otherwise...VFR conditions
through the TAF forecast period. Southeast to southerly winds 10 to
20 knots will diminish to 5 to 15 knots after 06Z to 08Z Tuesday.
Winds are expected to shift to the north and northeast 10 to 20 knots
following the passage of a cold front at the Guymon and Dalhart TAF
sites after 13Z to 15Z Tuesday and will remain from the south at the
Amarillo TAF site through 00Z Wednesday.

Schneider

Prev Discussion... /Issued 335 PM CDT MON MAY 30 2016/

Discussion... The main focus for this forecast remains on the
potential for strong to severe thunderstorms and locally heavy
rainfall over the next few days. Chances for rain will continue
across the region through the middle of this week, before tapering
off as an upper-level trough pulls eastward and a ridge of high
pressure builds in across the southwestern U.S. Details are below.

Short Term...Today and Tonight...
Synoptically speaking, analysis of water vapor imagery this
afternoon indicates the presences of several compact upper lows
across the CONUS as well as several shortwaves embedded in the upper-
level flow. Of primary interest for this region, a closed low was
situated over Arizona with weak downstream ridging over West Texas. A
shortwave ahead of this low was noted moving over eastern NM early
this afternoon. A closed low was also located over southern
Saskatchewan with a shortwave roughly in phase with the southern
stream wave. Both of these features will be moving over the High
Plains throughout this afternoon and evening, aiding in thunderstorm
development for the region. Radar echoes are already beginning to pop
up over the Rockies and Sangre de Cristos. Meanwhile a lee side
surface trough in eastern NM/CO was helping to re- establish
southerly winds across the Panhandles and draw low-level moisture
back into the area.

Modest capping across the Panhandles may limit convective initiation
across the Panhandles this afternoon, though enough destabilization
could occur by late this afternoon/early evening to see storms
develop in the western Panhandles. Otherwise, precip and
thunderstorm chances will be tied to mountain convection moving
eastward and tapping into elevated instability in this evening and
overnight. Generally weaker bulk shear values (20-25 kts of 0-6km
bulk shear) mean that loosely organized multicells are the favored
storm mode. A developing LLJ and increasing low-level moisture could
sustain thunderstorms into the evening hours. If coverage is great
enough and a cold pool should develop, chances for damaging wind
gusts will increase. Otherwise the risk will mainly be from hail and
locally heavy rainfall. A cold front will also begin edging into the
northern Panhandles tonight and could serve as an additional focus
for thunderstorms tonight.

NF

Long Term...
The aforementioned cold front will be in the region tomorrow and
should push through the Panhandles by late evening. The front should
provide a focus for storm development as moist southerly flow in the
low to mid levels converges along the front. There is some threat for
severe weather with thunderstorms that develop tomorrow, though
weakly sheared storms will again struggle to keep sustained updrafts.
Forecast soundings show the atmosphere quickly saturating with the
influx of moisture, and a transition to heavy rain as the primary
threat by late afternoon. Rain chances may persist into Wednesday as
moist upslope flow continues and the upper-level trough axis passes
overhead. Steering flow becomes extremely slow by Tuesday night, so
flash flooding will continue to be a concern if storms develop over
areas which have already received rain in recent days.

For Thursday and beyond, a ridge of high pressure is expected to
build over the western CONUS. The Panhandles will be on the eastern
periphery of the ridge and will only have slight chances for precip
during this time should any mountain convection make it into the
Panhandles. Temperatures will also rebound to near or above normal
during this time.

NF

Hydrology...
Very heavy rain in recent days has led to near saturated soils in
some locations. These areas will be most likely to experience
localized flooding or flash flooding with additional heavy rainfall,
though the possibility for heavy rainfall over the next few days
means that any portion of the area could experience flooding
concerns. Be alert for areas of standing water or rapidly flowing
water, especially in low-lying areas and low water crossings.

NF

&&

.AMA Watches/Warnings/Advisories...
TX...NONE.
OK...NONE.

&&

$$

11



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