Relevevant to next weekend section of AFD according to FWD:
The most noteworthy potential of the extended forecast exists
Friday night into next Saturday. By most indications, a Hudson Bay
vortex will deepen during the first half of the week, while
heights will build from Alaska towards the North Pole. Resultant
cross-polar flow will dislodge very cold surface air southward
into southern Canada and the northern Plains by mid/late week.
Meanwhile, medium-range deterministic and some ensemble guidance
suggest a Pacific impulse will undercut the aforementioned western
ridge and cross the Plains through the day Saturday. As an
attendant surface cyclone develops across the south-central US,
strengthening northerly flow behind the wave will draw this cold-
air reservoir southward over Texas.
Of higher confidence is an expectation that temperatures will
become quite cold on Saturday, with some locations perhaps
remaining in the 30s during the day. Indeed, the potential exists
for highs to be lower than what is currently advertised, but did
not want to be too aggressive with the forecast at such an
As for any winter-weather potential, large uncertainty exists with
the spatial and temporal evolution of the broader mid/upper trough
and the associated surface low. Most guidance indeed indicates a
positive tilt with the passage, suggesting any substantial
deepening and related mass response (impacting precipitation
potential) will be highest to our east. However, the ECMWF has
been trending towards a somewhat deeper solution and farther
southward advance of the synoptic trough, which would increase
winter weather potential, especially towards the Red River.
Meanwhile, the GFS and a notable number of its ensemble
counterparts maintain a slightly more progressive, less amplified
system, with rapid drying in its wake, ending any light
precipitation well before snow/sleet is possible.
So what`s a meteorologist to do with this conundrum? Well, a
slightly more amplified system (e.g., the ECMWF portrayal) does
not seem unreasonable, especially given the thrust of cold air and
baroclinicity that will be present. However, the antecedent
synoptic pattern will be characterized by relatively fast, zonal
flow ahead of this wave, which would favor a quicker eastward
cyclogenetic evolution that would be drier for North and Central
Texas (e.g., the GFS solution). Given that the answer most likely
(but still with low confidence) lies somewhere between those two
solutions, and also considering the very complex upstream/Pacific
pattern impacting the approaching wave, think it is too soon to
introduce any winter weather into our forecast. Therefore, have
maintained only low chances for rain showers Friday into Saturday,
before conditions dry out (with higher confidence) Saturday
night. Regardless, keep checking back for updates, as the forecast
will change (and that`s a 100% confidence forecast).
As we get closer we need to hope the Euro to keeps trending deeper and a little further south and have the others start chasing it. I know that’s obvious but I think by typing it, our chances improve.