Next 10 days: Developing Intense Negative North Atlantic Oscillation. So…
Arctic Gale New England Coast Friday Night
Major Snowstorm SUN/MON East Coast; Rain/Flooding at Coast
Ice Storm Texas Later Next Week
Ouch! GFS projects 271 HDD for Jan. 21-27
Fig. 1: The 12Z GFS Friday night forecast for the U.S. identifies a potent 970 MB low pressure system south of Nova Scotia forcing an arctic gale into New England.
Discussion: Development of a major coastal storm early this weekend is fortunately far enough offshore to produce most of the heavy snow northward into Nova Scotia early this weekend. However, on the back side of this 970 MB low-pressure system an arctic gale will clobber the New England Coast (Fig. 1). Wind chill temperatures of -10 to -30 occur as temperatures drop to zero in Maine and potential single numbers into southern New England accompanied by gale to storm force wind. North-facing beaches hit with ocean flooding. Freezing ocean spray a major issue. A wind chill chart is provided for this event (Fig. 2).
Fig. 2: Wind chill reference chart. Important when arctic air and wind are present.
Fig. 3: The 12Z GFS indicates a major East Coast storm for late this Holiday Weekend.
Discussion: The midday GFS develops a potent low-latitude storm on Saturday which wraps up into a 970 MB low-pressure near the northern Mid-Atlantic Coast by late Sunday. This storm will bring a plethora of issues near the coast including snow, freezing rain and ice over to rain with high wind and coastal flooding. Inland areas can expect a pile of snow likely in the 10-20 in. range with higher amount in favored areas especially the Appalachians (Fig. 3).
Fig. 4: The 12Z GFS indicates a freezing rain/icing event for ERCOT Jan. 20-21.
Discussion: In the -NAO pattern cold risk includes the Gulf States. The set-up is favorable for a low-latitude ice storm. The 12Z GFS indicates an ice storm risk for Texas Jan. 20-21 (Fig. 4). Hardest hit would be central, west and southwest Texas.
Midday 12Z GFS gas population weight HDD forecast: The 12Z GFS is incorrectly warmer over Lake Huron in the 6-10-day period (Fig. 2). Additionally, the warm anomalies over the Great Basin are overdone. The 11-15-day forecast trends colder in the Gulf States especially Texas/ERCOT (Fig. 3).
|Dates||HDD Forecast||12-Hr Change||24 Hours Ago||10-Year NML||30-Year NML|
Table 1: Indicated is the 12Z GFS projected gas population weight HDD for the U.S. compared to 12 and 24 hours ago through late January.