Interesting Scenario with extremely cold air flooding into Florida

Tampa Bay Effect "snow flurries” — perhaps, but too light to measure. I wouldn’t be surprised to see some snowflakes along both the Gulf coast to Tampa Bay, but much better bet along the Atlantic coast from Jacksonville to Daytona Beach along the beaches as the very back edge of the Arctic air + storm system moisture combine.

Snowfall is possible (very light) in Atlanta and Northeast Georgia with heavier amounts into the Carolinas and then up the East Coast. ECMWF 06z QPF amounts as snowfall (multiply by 10:1 or 15-20:1 for actual fluff factor)

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1. Development of a massive coastal storm —> major impacts for Mid-Atlantic and Northeast. Overnight and early morning model guidance has clustered around the ECMWF + AIFS solutions with GFS 06 edging slightly eastward

2. This will be a MASSIVE storm system but so far will track just far enough off the East Coast to hopefully avoid major impacts. That’s the main uncertainty: the distance of the very large system’s low pressure center from the coastline to allow the backside of the storm to dump snow.

Headline Snowfall Amounts from GFS 06z | Next 5-days

Snowfall Amounts from ECMWF IFS 06z | Next 6-days

QPF Precipitation Typed as Snowfall | No worry about freezing rain and sleet/ice

1.7” to 2.0” of QPF as snowfall would put eastern Mass in the 24” to 36” snowfall category with 15:1 to 18:1 Snow-to-liquid ratios

Variability in Snowfall Amounts Based Upon Track of Bomb Cyclone

We use ensembles (here EPS 06z from ECMWF w/51 member) to show the median or the rest of the solution distribution at every grid point

The spread is often best shown by the 75th percentile minus 25th (interquartile range) from “box and whiskers” statistics

75th Percentile — note this is 10:1 ratios so multiply by 1.5 factor due to cold air

ECMWF AIFS Snowfall Next 5-days

A bit eastward with AIFS — which would mean less snowfall in New England, but more in the Southeast and Carolinas.

Current Weather: Lake Effect Snowfall will continue to pile up especially downwind of Ontario in New York. Moisture returns to the Pacific Northwest

RTMA | Morning Temperature Analysis | 8 AM ET

8 AM ET: Average Lower 48 temperature was 19.8°F — 243 million below freezing.

Temperature Anomaly | 8 AM ET

8 AM ET: Lower 48 Temperature Anomaly below normal by -7.9°F

NWS NDFD Snowfall next 3-days | Lake Effect until they freeze over

Also, starting to see the “bomb cyclone” initial stage develop snowfall in North Carolina showing up

Continuing Brutal Cold

ECMWF Temperature Anomaly Next 6-days

Bottom drops out again this weekend with Florida under threat of a devastating freeze with teens and 20s to Interstate 4 and potential for Miami to see low-30s.

High Temperatures Today | Wednesday

Still 148 million freezing during day, but warming underway across Texas and the South into the 40s and even 50s with sunshine. Only 27 million above 70°F

60s return to central and south Florida as well as Texas.

Record Lows for all of Florida Sun + Mon | Hard Freeze | Pipe Busting Cold

Note the shape of the coldest air not aligning perfectly with the peninsula but bent to the east with contribution from the Gulf —> not the coldest possible scenario from ECMWF 06z

The wind vector is just offset east of what’s perfect for the coldest air into Miami.

NWS says mid-20s in Orlando and low to mid 30s in South Florida.

Sunday and Monday Low Temperatures

ECMWF IFS 06z | Precipitable Water Next 6-days

Moisture surges northward from the Gulf and Atlantic to fuel our “bomb cyclone” this weekend. Bone dry Arctic air mass “flushes” right through South Florida into Sunday with perhaps the perfect angle to bring a freeze to the Everglades.

Flagship ECMWF 12z EPS | Temperature Anomaly | Next 15-days

Looking into Days 11-15, there is an attempt to bring the westward warmth across the Rockies, but not so much … we may be seeing the opening up of the entire Arctic “ridge bridge” and Polar Vortex cold southward yet again for second 10-days of February.

ECMWF AIFS-Single 18z | Temperature (500 hPa) Next 15-days

The temperature at 500 mb is the easiest way to highlight the “polar vortex” across North America with the coldest pool at -40°C (pink) with the -25°C contour usually associated with below freezing temperatures at 2-meters (surface).

Blend of Models | 5 Days Precipitation Total

Blend of Models | Total Snowfall Next 5-Days

Blend of Models is on board with coastal snow — but since it’s an averaging of multiple models, it is likely way too wide/large with the snow swath. The EPS 06z median and IQ range are still better in my opinion at this juncture.

Temperature Anomaly | Next 15-days | ECMWF EPS 12z

5-Day Chunk #1 | Temperature Anomaly | Jan 28 - Feb 1

5-Day Chunk #2 | Temperature Anomaly | Feb 2 - Feb 6

5-Day Chunk #3 | Temperature Anomaly | Feb 7 - Feb 11