The Pennsylvania Observer

Transcription

1 The Pennsylvania Observer The Pennsylvania Observer September 16, 2004 Recap of Pennsylvania's weather from August 6 - September 12, (1 of 3)6/12/ :12:23 AM

2 The Pennsylvania Observer August 6th-14th Temperatures during the second week of August were slightly below average for the state, reaching the mid-70s to low-80s due to a large high pressure system located over the Mid-West and Mid-Atlantic states. On the 10th - 14th, substantial rainfall was seen throughout the state, beginning in the northwest and continuing southeastward through the rest of the region as a weak cold front slowly pushed through and moisture from Bonnie moved northward. Some eastern counties of Pennsylvania also saw rain from the remnants of Hurricane Charley as it moved through the Northeast. August 15th-21st High pressure began to build back into the Commonwealth on the 16th as conditions dried out and temperatures rose back above 80F. High humidity plagued PA as another cold front approached from the west, which packed more precipitation ahead of it in the form of severe thunderstorms. Counties in western and central PA saw the majority of the severe weather in the afternoon. Most of the state measured above one inch of rain for this week. August 22nd-August 30th Enjoyable weather finally stayed around a bit longer for the final week of August. The rain came in the form of isolated thunder showers on the 27th through the 29th along with uncomfortable humidity and temperatures in the 80s. As school began during the last week of August, comfortably warm temperatures returned to the region with mainly sunny skies. August 31st -September 12th Temperatures remained near 80F into the first week of September. The remnants of Hurricane Frances summoned cloudy conditions throughout the week. The cloud cover, along with a cold front that became the avenue for the tropical system on the 6th, kept western and central PA on the cool side with little variation in temperature throughout the day. Heavy rain arrived on September 8-9 as the eastern half of the state measured between inches and central and western Pennsylvania tallied between 2 and 6 inches of rain. The second weekend of the month had the most pleasant weather in several months. Here are the weather extremes (observations taken at 8 AM EDT) for the period 8/6-9/12 from the NWS Cooperative & ASOS Networks of which our office receives routine observations. Parameter Location Value Date (8 AM EDT) County (2 of 3)6/12/ :12:23 AM

3 The Pennsylvania Observer Highest Temperature Philadelphia, Doyelstown & York (ASOS) 91 F Lowest Temperature Kane (COOP) 32 F Greatest 24 Hour Liquid Precipitation Greatest Cumulative Liquid Precip. Altoona (ASOS) 5.72" Tobyhanna (COOP) 13.67" August 21, 2004 August 22, 2004 September 9, 2004 August 6- September 12, 2004 Philadelphia, Bucks & York McKean Blair Monroe Malingowski/Ayers goto page (3 of 3)6/12/ :12:23 AM

4 The Pennsylvania Observer There is a treasure trove of information on the Pennsylvania State Climate Office web page and each edition of this newsletter will highlight one of these gems so that you can gain even more for your visit to the web site. This newsletter features the Regional Climate Data page: Regional Climate Data Center The regional climate data center contains a wealth of data describing each of Pennsylvania's 10 Climate Divisions. The data is available for the following parameters: temperature precipitation snowfall And over the following time scales: monthly seasonal (1 of 4)6/12/ :12:31 AM

5 annual 30-year means The site contains both actual numbers and departures from normal. Why This Archive Is Unique This archive contains historical data that stretches from the present day all the way back to With the exception of the most recent months, this data has been selected by the National Climatic Data Center to "officially" represent the conditions within the individual climate regions. This data can prove invaluable when attempting to approximate long-term conditions and/or trends across a specific area of the state over the past century. However, the process of verifying regional climate data takes NCDC several months to achieve. Fortunately, the Regional Climate Data Page comes to the rescue. Preliminary data is taken from several sites within each region to create an estimated "unofficial" measurement for each climate region. These data are available within a few days following the end of each month, rather than the lag time of several months for official data. Although "unofficial", these proxy stations have been carefully selected to mimic the official NCDC sites, usually to within 10% of the official precipitation amounts and to +/- 0.5 degrees for temperatures. These preliminary values are noted as such by an asterisk along side the value. Upon completion of NCDC's verification process, the preliminary values on our site are replaced with the official values. Here is an image of what the site looks like: (2 of 4)6/12/ :12:31 AM

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7 To access this product: 1. Go to our home page: 2. Go to the drop box marked: Choose Data Type 3. Select the "State Data" option in the drop box 4. Click on the red button that says "Regional Climate Data" or Follow the this link: We hope you will peruse this part of the web page and if you have any questions, please contact us at Greybush goto page (4 of 4)6/12/ :12:31 AM

8 The Pennsylvania Observer Climate Highlight FEATURED CLIMATE HIGHLIGHT PENNSYLVANIA LONG RANGE FORECAST: Expected Temperature and Precipitation Departures for November and December 2004 by Climate Division (1 of 6)6/12/ :12:39 AM

9 Precipitation over the summer of 2004 was much above normal. Across Pennsylvania's ten state climate divisions, there was on average 6.13" more rainfall than average over June, July and August. This abundance of precipitation made for the 5th wettest summer on record. Temperatures over the entire state were cooler than average, as this summer ranked 83rd warmest out of 106 years. Here is a summary of Summer 2004 by Climate Division: (DFN=departure from normal) Division Temp DFN Temp Rank Precip DFN Precip Rank F 72 of " 2 of F 64 of " 1 of F 75 of " 1 of F 93 of " 5 of F 80 of " 7 of F 77 of " 1 of F 75 of " 4 of F 105 of " 13 of (2 of 6)6/12/ :12:39 AM

10 F 84 of " 5 of F 103 of " 13 of 106 AVERAGE -1.3 F 83 of " 5 of 106 Using these anomalies as a basis, the PA Climate Office has produced a divisional forecast of expected departures from normal for temperature and precipitation in November and December. The following methodlogy was used in producing the divisonal outlook: 1) Identify and rank the wettest summers (prior to 2004) on record. 2) Starting from the summer of greatest precipitation, find the six years with the wettest summers that were also below normal in summer temperatures. 3) Obtain temperature and precipitation departures from normal in November and December for each of those years. 4) Calculate the average temperature departures from normal for all analog years. 5) Calculate the precipitation departures from normal for all analog years. 6) Results represent expected temperature and precipitation departures from normal for November and December PREDICTIONS: (3 of 6)6/12/ :12:39 AM

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12 PRECIPITATION: Precipitation should average somewhat above normal for both November (average of +0.56" DFN) and December (average of +0.45" DFN) throughout the state. TEMPERATURE: There is a strong correlation between cool, wet summers and cool November temperatures. Temperatures should be below normal in all areas of the state (average DFN of -2.3 F) during the eleventh month. December shows a wide range of possibilities for each climate division and thus provides no clear trend with this set of analog years. Overall, temperature departures round out to near normal (average DFN of +0.2 F). Greybush visit the Climate Highlight Center... (5 of 6)6/12/ :12:39 AM

13 return to the Pennsylvania Observer center.. visit the Pennsylvania State Climatologist home page... (6 of 6)6/12/ :12:39 AM