Weather Briefing for Pennsylvania January 5-8, 2014 Prepared 01/05/14 (1:30 PM EST)

Transcription

1 Weather Briefing for Pennsylvania January 5-8, 2014 Prepared 01/05/14 (1:30 PM EST) Prepared by: National Weather Service State College, PA

2 Latest Radar

3 Latest Surface Weather Plots Freezing Rain

4 Pennsylvania Weather Overview Weather Synopsis: A rapidly developing storm system will move into Ohio by nightfall. Some light freezing rain or drizzle is likely ahead of the storm before temperatures recover above freezing later this afternoon and evening. An arctic cold front with EXTREMELY COLD AIR will traverse the Commonwealth late tonight and early Monday morning. This will usher in below zero temperatures and wind chills of -20 to -40 degrees through midweek. Temperatures will fall and the wind will increase throughout the day Monday.

5 Weather Progression and Timing Precipitation in the form of freezing rain or drizzle will continue to spread northeastward through mid afternoon. Mainly over central and eastern Pa. Temperatures should recover to above freezing in all areas by late afternoon or early afternoon diminishing the icing threat. Predominant precipitation type overnight will be rain. Cold front will move through after midnight. Rain showers will change to snow showers over western and central areas by morning. A flash freeze is possible over western areas as cold air rapidly pours into the region.

6 Summary of Watches and Warnings Freezing Rain advisory eastern half of the state Through early evening Generally a one to two tenths of an inch of ice Wind Chill Warning western Pa Monday afternoon - Wednesday morning Winter Storm Watch for Erie and Crawford Counties Sunday night through Tuesday afternoon Heavy lake effect snow and blizzard conditions Wind Chill Watch west-central PA Monday Afternoon Wednesday morning

7 Cold Temperatures Temperatures will start falling behind the cold front which is slated to cross the Commonwealth overnight Sunday Night and Monday morning Front will enter western PA around midnight. The front should be exiting eastern PA by mid morning Monday Behind the front temperatures will steadily fall and winds will increase Wind chills Tuesday Night ranging from -10 to -30

8 L L Midnight Mid Morning Monday

9 Cold Temperatures Arctic air will flood the region into Wednesday morning Lows Monday Night ranging from near -15 in the NW to around 0 in the SE Wind Chills ranging from -20 to -40 Highs Tuesday ranging from Zero to -5 in the NW to the lower teens in the SE Wind chills Tuesday ranging from -10 to -30 Lows Tuesday Night ranging from near -10 in the NW to the single numbers in the SE Wind chills Tuesday Night ranging from -10 to -30 Temperatures will rebound Wednesday, with highs ranging from the teens in the NW to the middle 20s in the SE

10 Forecast Low Temperatures Monday Night Tuesday Morning

11 Forecast Wind Chill Temperatures Monday Night - Tuesday Morning Valid 7AM Tuesday

12 Forecast High Temperatures Tuesday

13 Forecast Wind Chill Temperatures during the day Tuesday Valid Mid Day Tuesday

14 Forecast Low Temperatures Tuesday Night

15 Forecast Wind Chill Temperatures Tuesday Night

16 Forecast High Temperatures Wednesday

17 Post Frontal Impacts: SNOW/ICE Some accumulating snow is expected in the northwest. Roads will become snow covered and slippery Lake Effect snows Monday Wednesday Winter Storm Watch for Erie and Crawford Counties Rain changing to snow showers expected in most other places Snow accumulations should be limited except in the NW A brief period of freezing rain is possible, mainly across central and eastern sections as temperatures fall. This could cause slippery road and walkway conditions, especially those that are untreated

18 Impacts: Freeze-Up A rapid cool-down expected Late Sunday Night and early Monday Any left over rain will quickly turn to snow in western and central Pennsylvania with the frontal passage Sub freezing temperatures will take a bit longer to make it into far eastern Pennsylvania. Wet roads and surfaces will quickly freeze as temperatures plummet below freezing. Watch for rapidly changing conditions: Flash Freeze! Timing of frontal passage should be favorable for limited freeze up for eastern half of the state (during Monday daylight hours)

19 Impacts: Cold Temperatures and Wind Chills Sub zero temperatures, and wind chills reaching -20 to -40 will create dangerous conditions Coldest period will be Monday Night into early Wednesday Morning Frostbite and hypothermia can occur Wind chills of -30 or colder can cause frostbite on exposed skin in as little as 10 minutes! For some areas of the Commonwealth, especially in the south...this will be the coldest air in 20 years (since Jan 1994)!

20 Observed Low Temperatures From January 1994 Arctic Blast Harrisburg -22 Williamsport -20 Altoona -20 Bradford -26 Chambersburg -21 Hanover -14 Lancaster -16 Lewistown -17 Lock Haven -17 New Holland -13 Philipsburg -25 Renovo -15 Selinsgrove -25 State College -18 York -21

21 Cold Weather Safety Wear layers of loose-fitting, lightweight, warm clothing. Trapped air between the layers will insulate you. Outer garments should be tightly woven, water repellent, and hooded. Wear a hat, because 40% of your body heat can be lost from your head. Cover your mouth to protect your lungs from extreme cold. Mittens, snug at the wrist, are better than gloves. Try to stay dry and out of the wind. Don t forget your pets!

22

23 Links to local NWS offices that cover Pennsylvania (Get the latest forecasts and updates!) NWS Cleveland weather.gov/cleveland NWS Pittsburgh weather.gov/pittsburgh NWS State College weather.gov/statecollege NWS Binghamton weather.gov/binghamton NWS Mount Holly weather.gov/philadelphia

24 Web Links Emergency Managers Briefing Page: PA Snow Accumulation Reports Display vent=stormtotal_12&element=snow&centeron=ctp