159 FXUS64 KAMA 042338 AFDAMA Area Forecast Discussion National Weather Service Amarillo TX 538 PM CST Mon Jan 4 2021 .AVIATION... 00z TAF Issuance...VFR conditions are expected at all three TAF sites through the period. Winds are light and variable this evening and through the overnight hours. By the morning hours, winds will be out of the south southwest and pick up to around 10 to 20 knots through the day with gusts up to 30 knots possible. Low level wind shear out of the southwest at around 40 knots is possible during the morning hours at GUY. Skies will be mostly clear with some broken/scattered high clouds possible throughout the period. Rutt && .PREV DISCUSSION... /Issued 224 PM CST Mon Jan 4 2021/ SHORT TERM...Tonight through Tomorrow Night... A transient upper level ridge is currently moving across the intermountain west in advance of the next shortwave trough. Northwest winds aloft will gradually become more zonal as the ridge traverses the plains tonight into tomorrow. Zonal H7 to H5 winds will increase tomorrow as the shortwave makes its way across the southern and central Rocky Mountains. The increasing cross barrier flow will help induce lee surface troughing and gusty southwest winds as mixing becomes more prevalent into Tuesday afternoon. The combination of gusty downslope winds and modestly dry conditions will warrant elevated fire weather conditions across most of the Texas and Oklahoma Panhandles during the afternoon hours (see fire weather discussion below). These conditions will also help boost high temperatures into the 60s across the area. As the upper level shortwave moves out into the plains Tuesday night, models do bring a southern branch of PVA across the northern zones mainly around 00z Wednesday. However, model soundings suggest a dry environment ahead of the system, with only a marginal increase in moisture with the system as a cold front moves through. Thus, keeping the forecast dry at this time (even though the EC is trying to spit out a few sprinkles Tuesday evening along the front in the far northwest zones). The cold front will result in pressure rises of about 2mb/hr for at least a few hours, so winds will be breezy to windy overnight Tuesday. Ward FIRE WEATHER...Tuesday Afternoon... The combinations of southwest twenty foot winds of 20 to 25 mph and ERC values around the 50th percentile will result in elevated fire weather across most of the combined Panhandles Tuesday afternoon. The exceptions are the far northwest zones due to weaker winds and the far southeast zones due to lower ERC percentiles. RFTI values of 2 to 3 can be expected, and are entirely due to the stronger winds. Relative humidity values do drop down to around 20 to 25 percent across all but the southeast Texas Panhandle. Conditions should improve going into the early evening as temperatures drop and wind speeds start to back off. However, a cold front will result in a wind shift to the north and another spike in the wind speeds between 6 PM and 11 PM Tuesday evening. Ward LONG TERM...Wednesday through Sunday... Extended is fairly benign except for the system coming through on Sunday which may bring some wintry precip to the area. Wednesday will see the next shortwave trough exiting the area and the mid-level closed low shifting southeastward. This will put us in northerly flow aloft until around Thursday when the low gets far enough to the east to ease winds back to northwest flow as ridging fills in. The ridging will be short lived as another shortwave looks to come across the Plains Friday. Just as that shortwave arrives, the next major low comes onshore in the Pacific NW. It is expected to dive quickly across the west and head for the southern Plains over the weekend, focusing on Sunday. Models are in disagreement of the position and speed for this system. The deterministic GFS is faster and more northerly while the deterministic ECMWF is slower and further to the south. Only a handful of the GEFS and ECMWF members show this northern track. If the northern track pans out, the Panhandles could see some snow. If the southern track pans out, we would mostly be missed by the better moisture. NBM on this run has trended towards the southern track and lowered PoPs. Will continue to monitor the system for trends from run to run. Beat && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 23/11