Site log - Houston (Feb 1998) Flags: 1-Satellite coincidence data 2-Scan in TSDIS data 3-Scan not in TSDIS data A-Major problem (moderate to strong AP &/or widespread coverage) B-Minor problem (weak AP &/or very litte coverage) **************************************************************************************** 01 Feb 98: Widespread light rain to moderate precip (mostly in W and N regions) thru 03Z. Multicell complex moves in from SW after 03Z and grows in size and intensity. A cell forms on the NE edge of this system near 0530Z, then breaks away and moves over the radar by 07Z. Cell is very intense and stays intact thru 10Z (displays a kidney bean shaped reflectivity structure at times...pronounced inflow notch?). Meanwhile, the multicell complex to the SSE continues to intensify and becomes a mature MCS near 07Z. Near 0830Z, displays bow echo signature. By 10Z, the system reorganizes and continues to move to the ENE. Heavy precip from this sytem moves out near the end of the day. A region of light to moderate precip moves in from SW near end of day, too. Data processed: 0004-2359Z Satellite Coincidence: 0009Z, 0146Z, 0322Z, 0459Z, 2120Z, 2256Z QC notes: 0004-2159Z: A few holes and gaps in lighter precip -----> corrected, but the following flags result, mostly for clutter specks that are captured by nearby lighter precip. ----------------------------------------------------- 1B, 2B, 3B !!FLAG!! 0004-0247Z: Clutter specks 1B !!FLAG!! 0318-0333Z: Clutter specks 3B !!FLAG!! 0413-0418Z: Clutter specks 3B !!FLAG!! 0533-0538Z: Clutter specks (0543Z used in 1C.HDF since it's cleaner) 3B !!FLAG!! 0603-0618Z: Clutter specks (0623Z used in 1C.HDF) 2B, 3B !!FLAG!! 0628-0705Z: Clutter specks (0710Z used in 1C.HDF) 3B !!FLAG!! 0736-0751Z: Clutter specks 3B !!FLAG!! 0806-0826Z: Clutter specks 2B, 3B !!FLAG!! 0836-0916Z: Clutter specks 2A, 3A !!FLAG!! 0921-0956Z: More widespread clutter specks as light precip moves right over radar 2B, 3B !!FLAG!! 1001-1026Z: Clutter specks 3B !!FLAG!! 1147-1157Z: Clutter specks 3B !!FLAG!! 1237Z: Clutter speck 2B, 3B !!FLAG!! 2024-2049Z: Some clutter introducted near radar. There are probably some showers embedded in the clutter, though, as higher tilts reveal vertical and temporal continuity. 1B !!FLAG!! 2059-2104Z: Light remants of a radial spike to SW. Increasing params resulted in back edge of precip to E to be eaten away, thus kept the params lower and flagged these two VOSs as minor. ----------------------------------------------------- 2209-2224Z: Light AP specks to SW ----> Corrected (a small light speck or two, but nothing significant. Raising params further resulted in reduction of precip to east) Note: 0543Z included in 1C.HDF instead of 0533-0538Z 0623Z included in 1C.HDF instead of 0603-0618Z 0710Z included in 1C.HDF instead of 0700-0705Z **************************************************************************************** 02 Feb 98: Two large stratiform precip shields (SE and SW) w/ some convective elements move ENE thru ~09Z. Flow seems to change and precip remains stationary or moves slightly to SW. New area of precip forms near radar and moves to SW after 09Z. By 14Z, widespread light to moderate precip forms and persists for most of the day (begins to move out & dissipate near end of day, though). Data processed: 0004-2355Z Satellite coincidence: 0033Z, 0210Z, 0346Z, *2144Z*, 2320Z 2144Z overpass 161 km QC notes: Whole day: Second tilt precip adversely affected by H3 (precip eating mode in second tilt). Also, the below flags: 0049-0054Z: Clutter speck near radar as precip moves near radar 1B+ !!FLAG!! ----> Difficult to remove. Raising H3 to over 4.0 km helps, but this has an adverse affect on the second tilt image. 0059-0104Z: Clutter speck to NW as precip moves near it. ----> Corrected 0456Z: Clutter speck to NW ----> Corrected 0646-0656Z: Clutter speck to NW ----> Corrected 1001-1157Z: Light precip eliminated 2B+, 3B+ !!FLAG!! ----> Much of the light precip brought back, but embedded clutter specks (mostly small and not widespread) are also in CZ. ----------------------------------------------------------------------- 1302-2355Z: Light precip eliminated ----> Corrected, except for the below flags 2B, 3B !!FLAG!! 1302-1322Z: A few embedded clutter specks 2A, 3A !!FLAG!! 1327-1728Z: More widespread embedded clutter specks as light precip forms over the radar. Not much can be done about it! 2B, 3B !!FLAG!! 1733-1803Z: Still a few embedded clutter spots. Using 1808Z in 1C.HDF instead of 1803Z. 2B, 3B !!FLAG!! 1829-1909Z: Still a few embedded clutter spots. Using 1914Z in 1C.HDF instead of 1904 or 1909Z. 1A, 2A, 3A !!FLAG! 1939-2144Z: Persistent embedded clutter specks as light precip forms/moves over the radar. 1B !!FLAG!! 2149Z: A few clutter specks 2B+, 3B+ !!FLAG!! 2229-2249Z: Speck to NW embedded in light precip. Note: 1808Z included in 1C.HDF instead of 1803Z 1914Z included in 1C.HDF instead of 1904-1909Z. **************************************************************************************** 03 Feb 98: Light to moderate showers through 0411Z. Data Processed: 0000-2351Z Satellite Coincidence: 0057Z (598 km), 0234Z (122 km), 2031Z (597 km) 2207Z (272 km), 2344Z (627 km) QC Notes: 0000-0411Z: Some fringes of lighter precip eliminated ----> Corrected, except for below flags 1B, 2B, 3B !!FLAG!! 0025-0201Z: Still some clutter specks mostly embedded in the light to moderate precip. Opted for a minor flag since the precip often masks the specks fairly well. If it was all very light precip, I would've gone 'major' since the specks would've been all the more obvious. -------------------------------------------------------- 2213-2351Z: AP specks to E -----> Corrected. Some precip at 2213 is eliminated, but it's greater than 150 km away. **************************************************************************************** 04 Feb 98: A few showers to S between 0209-0327Z, & 2117-2235Z. Data Processed: 0001-2353Z Satellite Coincidence: 0121Z (398 km), 0257Z (368 km), 2055Z (53 km), 2231Z (541 km) QC Notes: 0001-0159Z: AP specks to E -----> Corrected 0209-0327Z: AP specks to E combined w/ showers to S -----> Corrected 0337-0554Z: Continued AP specks to E -----> Corrected 1118-1454Z: AP specks and splotches of varying degrees, widespread at times in NW sector. -----> Corrected 1652Z: AP speck to SW -----> Corrected 1820-1830Z: AP speck to E -----> Corrected **************************************************************************************** 05 Feb 98: Light precip moves in from W after 07Z. Heavier line of precip w/ embedded convection enters domain after 12Z and gradually weakens as it moves ENE. By 16Z, mostly light to moderate precip in N. Near 17Z, organized convective system moves in from SW. Heavy convection mostly isolated to extreme S, but a large swath of moderate w/ embedded heavy precip forms from the combination of this system w/ a pocket of precip to the NE by 19Z. Scattered precip behind the large region of precip to the W/SW. Data Processed: 0004-2043Z Satellite Coincidence: 0005Z (570 km), 0145Z (25 km), 1942Z (461 km), 2119Z (349 km), 2256Z (630 km) QC Notes: 0023-0656Z: Scattered specks and splotches of AP, sometimes widespread in the NW sector (varies from light to intense). -----> Corrected --------------------------------------------------------- 0735-0956Z: Lighter precip eliminated -----> Mostly corrected (some very small, light <5 dBZ, showers may still be removed. A few VOSs have AP specks and are flagged below: 3A, 3B !!FLAG!! 0936, 0941, 0951, 0956Z: AP specks/sploches remaining. Increasing params further wipes out most lighter precip to W. 0936 has very intense speck and could be considered a major problem, the rest of the VOSs have light AP and are considered minor. --------------------------------------------------------- 1006-1051Z: Intense pockets of AP to SW and E 3A !!FLAG!! -----> All tricks to get rid of AP did not work very effectively for this time period. Raising H1 and/or Z1 was effective in removing AP, but the light, shallow precip to W was always eliminated in the process. Raising DBZNOISE helped (esp. 1026Z), but was not a cure-all, either. Using 1056Z in 1C.HDF for second half of this granule. Otherwise, everything else is flagged. 1056Z: AP speck to SW 2B !!FLAG!! -----> Not perfect, but a much better VOS than any others. 1101-1331Z: Lighter precip eliminated -----> Corrected 1336-1356Z: Lighter precip eliminated 3B !!FLAG!! -----> Some clutter specks picked up in light precip near radar 1401-1456Z: AP specks and splotches to E/NE...very intense in many VOSs 2B, 3A !!FLAG!! -----> Using 1406 and 1446 in 1C.HDF since they're the cleanest images (flagging them as 2B since some light AP is evident). Most other VOSs in this hour are flagged 'major' because of the intense AP. AP can be removed by raising H1, or through a combo of raising H0, Z1, and lowering Z3 (this combo has been successful in previous AP cases), but most of the lighter precip is removed and all that remains are the cores of precip > 25 dBZ or so. H1=2.5 helps a little for most VOSs, but intense AP remains. 1501-1657Z: Continued AP to NE, often intense and embedded in precip shield. 2B, 3A, 3B !!FLAG!! -----> AP very difficult to remove because of light precip and/or AP embedded in precip shield to NE. VOSs 1501, 1551, 1602, and 1642 are used in 1C.HDF because they seem the cleanest and have the least amount of intense embedded AP, although there may be some lighter embedded AP in the precip, too. Other times have obvious moderate to intense AP. Raising params results in the same dilemma as 1401-1456Z period. Some 'normal' clutter speck contamination also occurs w/ light precip near radar. 1702-1742Z: Lighter precip eliminated + precip eating on back end of a small moderate/light cell just to SW and S of radar. 2A, 3A !!FLAG!! -----> Most of precip eating corrected, but lots of specks and clutter as near and w/in light precip --------------------------------------------------------- 1747-2043Z: Lighter precip eliminated -----> Corrected, except for the following flags. 3A !!FLAG!! 1752-1807Z: Clutter specks near radar. Using 1812Z in 1C.HDF 2B, 3B !!FLAG!! 1812-1907Z: Continued specks near radar, but not as widespread as before. 1A !!FLAG!! 1912Z: Some clutter specks combined w/ remants of radial spike to NW. 1A !!FLAG!! 1917-1958Z: More widespread clutter near &/or w/in lighter precip 1B, 2B, 3B !!FLAG!! 2003-2043Z: Some clutter specks near &/or w/in light precip --------------------------------------------------------- Note: 1056Z included in 1C.HDF instead of 1031-1051Z. 1406Z included in 1C.HDF instead of 1401Z. 1446Z included in 1C.HDF instead of 1431-1441Z. 1551Z included in 1C.HDF instead of 1531-1546Z. 1642Z included in 1C.HDF instead of 1632-1637Z. 1812Z included in 1C.HDF instead of 1802-1807Z. **************************************************************************************** 06 Feb 98: Region of light to moderate precip moves off to the ESE by 04Z. A few light showers to the W and NW persist thru 0824Z. No precip afterwards. Data Processed: 0056-0824Z 1441-2358Z Satellite Coincidence: 0032Z(326 km), 0209Z(501 km), 2007Z(56 km), 2143Z(579 km), 2320Z(528 km) QC Notes: 0216-0241Z: AP specks to E w/ light precip in the picture -----> Corrected 0256-0336Z: AP specks to E/NE w/ light precip in the picture -----> Corrected 0351-0511Z: AP specks and splotches to N/NW combined w/ light precip -----> Corrected 0516-0622Z: AP specks to NW and E combined w/ light precip 2B, 3B !!FLAG!! -----> Mostly corrected, but a few small AP specks remain. Very hard to keep all the light precip in and get rid of all of the specks. 0627-0657Z: Intense AP to SW 2A, 3A !!FLAG!! -----> A trade-off here...had to bump up the params to help remove AP, thus removing very light (~5 dBZ) showers to NW. Still some AP specks, though. The cores of the showers to the NW are kept in, though, and most of the AP is removed. Further increasing params only results in eliminating all precip, and AP doesn't go away until H2 is raised to over 5 km! 0707-0824Z: Light showers to NW mostly removed by defaults -----> Corrected 1832-1911Z: AP speck to ENE -----> Corrected 1931-1950Z: AP speck to ENE -----> Corrected 2020-2030Z, 2049Z: AP speck to ENE -----> Corrected **************************************************************************************** 07 Feb 98: Only precip on this day in the form of scattered light showers off the coast after 16Z. Data processed: 0008-2351 Z Satellite coincidence: 0057Z, 1854Z, 2031Z, 2208Z, 2344Z QC notes: 0057-0858Z: scattered weak-to-moderate-intense AP remaining -----> corrected 0937-1006Z: weak AP specks remaining -----> corrected 1135Z: weak AP specks remaining -----> corrected 1214-1441Z: scattered weak-to-moderate AP remaining -----> corrected **************************************************************************************** 08 Feb 98: Only precip on this day in the form of a small, short-lived shower out in the Gulf around 16-17Z. Data processed: 0001-2358 Z Satellite coincidence: 0121Z, 1918Z, 2055Z, 2232Z QC notes: 0158Z, 0416Z: moderate AP speck remaining -----> corrected 0544-0614Z: scattered weak AP specks remaining -----> corrected 0643-0732Z: scattered weak AP specks remaining -----> corrected 0811-1606Z: scattered weak-to-moderate-to-intense AP remaining -----> corrected 1616-1715Z: scattered weak-to-moderate AP present along with 2 shower cells SE of radar 2B !!FLAG!! -----> vastly improved and may be completely Ok in that the remaining weak AP may be beyond 150 km. Can not be sure (and it may not be true)...hence the flag. 1725-1932Z: scattered weak AP remaining -----> corrected **************************************************************************************** 09 Feb 98: Scattered very light echoes mostly in SE quadrant between 05-13Z, although much of it seems to be outside the 150 km range. E-W line of light showers pops up to N and NE of radar after 16Z. This line breaks up quickly (by ~18Z) and only scattered light echoes are observed thru 20Z. After 20Z, wave-like pattern of reflectivity develops over the gulf and moves NE thru 2357Z. Data processed: 0007-2357Z Satellite coincidence: 0008Z(204 km), 1806Z(202 km), 1943Z(479 km), 2119Z(606 km), 2256Z(153 km) QC notes: 0145Z, 0541Z: Light AP specks -----> Corrected 0700-0719Z: Light AP splotch to SW -----> Corrected 0759-0857Z: Light to moderate AP to SW -----> Corrected NOTE: The very light echoes in the SE quadrant are deemed insignificant since they are near 150 km and greater in range and are so light. AP would have to introduced in CZ if those echoes were to be included in CZ by lowering the params. 1213-1224Z: Light AP to SW...borderline 150 km -----> Corrected 1609-2157Z: Some very light echoes eliminated by defaults -----> Corrected **************************************************************************************** 10 Feb 98: An exciting day in the Lone Star State!! Light showers along coast E of radar 0002-0033Z. Scattered light showers begin near HSTN ~0935Z - this is the beginning of a great event. By 1421Z, widespread shower / thunderstorm activity with embedded 50 dBZ cells approaches from the West. By 1710Z, showers and deep, intense convection begins to surround radar. All of this activity is ahead of a massive 40-50 dBZ squall line approaching from the West. By 1915Z, the intense squall line is directly over KHGX radar. The squall line is oriented N-S and has a large area of heavy rainfall (30-50 dBZ) to the N of HSTN radar, near College Station. There is a TRMM overpass near College Station ~ 1830Z (1230 CST). By 2257Z, the squall line has moved well E of HSTN, while another area of showers / convection approaches from the West. Data Processed: 0002-1241Z 1421-2358Z Satellite Coincidence: 1654Z(643km), 1830Z(244km), 2007Z(623km), 2144Z(418km), 2320Z(328km) QC notes: Note: Several time periods exist where clutter was masked almost completely by moderate / heavy precip. No flags were given for these VOSs. During other periods, some moderate/ intense clutter was masked by light precip at the radar. These VOSs were only given "B" flags because of the close proximity of heavy (50 dBZ) echos. 0203Z: Second trip echo SW of radar - light precip present ----> Corrected. 0738Z: Dimming of reflectivities - this VOS only. Possible calibration problem 1531Z: Intense clutter specks near radar - light precip present ----> Corrected. 2B,3B !!FLAG!! 1541-1556Z: Clutter near radar with light precip over radar. Cannot remove clutter without also removing precip. 1B,2B,3B !!FLAG!! 1611-1621Z: Clutter near radar with light precip over radar. Cannot remove clutter without also removing precip. 3B !!FLAG!! 1750-1755Z: Clutter near radar with light precip over radar. Cannot remove clutter without also removing precip. 1B,2B !!FLAG!! 1805-1810Z: Ring of precip removed by default qc params very close to radar. Also, precip removed at mid-range by default qc params. The missing precip was reinstated, but clutter specks near radar could not be removed. 1930Z: Intense clutter specks near radar - light precip present ----> Corrected. 1B,2B !!FLAG!! 2000Z: Clutter near radar with light precip over radar. Cannot remove clutter without also removing precip. **************************************************************************************** 11 Feb 98: A large area of showers / convection developes W of radar and passes mainly S along the coast ~0128Z. Isolated cells with 50-60 dBZ maximum develop S of radar along the coast and push out into the Gulf. This intense activity dissipates and moves out of radar scope by ~04Z. Light showers develop in Gulf ~16Z. Additional showers and isolated storms develop in Gulf ~2045Z. It appears that the clutter filter was turned on at 0656Z. Data Processed: 0003-2351Z Satellite Coincidence: 1718Z(87km), 1854Z(528km), 2031Z(580km), 2208Z(56km) QC notes: 0013-0228Z: Light precip removed in second tilt images. Parameter H3 set too high. ----> Corrected The light precip was fully reinstated in the second tilts. 0013-0228Z: Also, many VOSs in this time period contained moderate to intense clutter specks and horizontal bars of clutter near the radar. ----> Corrected EXCEPT FOR FLAGS BELOW!! 2A,3A !!FLAG!! 0053-0103Z: Intense clutter specks and horizontal bar of clutter near radar. Light precip also present. Could not remove clutter due to presence of precip. 3A !!FLAG!! 0118-0128Z: Intense clutter specks near radar - could not be removed due to presence of light precip. 3A !!FLAG!! 0143Z: Intense clutter specks near radar - could not be removed due to presence of light precip. 2B !!FLAG!! 0203Z: Moderate clutter specks masked by light to moderate precip. Clutter could not be removed due to presence of precip. 3A !!FLAG!! 0218Z: Intense clutter specks near radar - could not be removed due to presence of light precip. ******************************************************************************************** 12 Feb 98: Area of showers / small convective cells developes NW of radar ~22Z, and moves N of radar. A possible density current triggers a spectacular undular bore (6 waves in the pattern!!) in the Gulf of Mexico. The wave patterns appear to originate from a point source and expands toward the NE. A large data gap exists from approx 1440Z-2150Z. The VOS at 2156Z is incomplete. It appears that the radar was turned off about 1440Z, and turned back on near 2156Z. The next VOS is from 2157Z, and appears to be fine. The 2156 uf file was placed in a "bad_files" directory so it would not be bundled into 1CHDF granule. Data Processed: 0001-1435Z 2156-2357Z Satellite Coincidence: 1605Z(505km), 1742Z(324km), 1918Z(630km) 2055Z(351km), 2231Z(456km) QC notes: 0030-1435Z: Moderate to intense AP S,E, and W of radar - no precip. ----> Corrected 2156Z: VOS is not complete - contains some clutter but no precip I wiped this VOS clean (see note above) 2237-2317Z: Light showers removed by default QC params near radar and at mid-range. ----> Corrected (note: some very minor clutter specks brought back with light showers but not significant enough to flag) Only one VOS had significant clutter specks (see flag below) 3B !!FLAG!! 2317Z: Clutter specks could not be removed due to presence of precip. 3B !!FLAG!! 2322Z: Second trip echo SW of radar - with light precip. Light precip removed by default QC params. Clutter specks near radar ----> Second trip removed within 150 km range. Precip reinstated Clutter specks could not be removed due to presence of precip --------------------------------------------------------------------- 2327-2357Z: Light showers removed by default QC params near radar and at mid-range. ----> Corrected EXCEPT FOR FLAGS BELOW!! 3B !!FLAG!! 2337Z: Moderate clutter speck could not be removed due to presence of light precip near radar 3B !!FLAG!! 2342-2347Z: Moderate clutter speck masked by light / moderate precip. --------------------------------------------------------------------- *********************************************************************************************** 13 Feb 98: Large area of showers / convection N & W of radar, with a stunning undular bore along coast and into the Gulf from 0002Z --> 0233Z. Intense line of convection developing W of radar near 150 km range at 0233Z. Unfortunately, the radar goes down after 0233Z. The next VOS (0612Z) is not complete, therefore, the 1C uf file has been placed in a bad files directory. A large area of showers / convection developes in Gulf while light showers develop near radar ~0616Z. Precip exits scope by 08Z. No more precip for remainder of day. Data Processed: 0002-0233Z 0612-1600Z 1837-2351Z Satellite Coincidence: 1629Z(19km), 1805Z(567km), 1942Z(544km), 2119Z(46km) QC notes: 0002-0208Z: Light showers removed by default QC params, mainly in bore over the Gulf. Major precip eating mode where Z0 has to be turned off to get the light bands of precip over Gulf in CZ. Most holes in precip solved, but a bunch of flags result below. 2A, 3A !!FLAG!! 0002-0027Z: Clutter specks, sometimes intense with light precip near radar. After generating a 2A-54 product from this data, some of the flags for clutter specks very near the radar may not be needed since there's a hole in the 2A-54 convective-stratiform map near the radar. Thus, many of these specks may be negligible very near the radar. Still flagged as major, though, until this thought is verified. 3B !!FLAG!! 0032-0037Z: Some clutter and light clear air echo. Using 0042Z in 1C.HDF instead of these VOSs. 3B !!FLAG!! 0047Z: Remants of a radial spike to SW...very light and mostly outside of 150 km. 2B,3B !!FLAG!! 0053-0113Z: Persistent clutter specks cannot be removed due to presence of precip. 2B,3B !!FLAG!! 0138-0208Z: Persistent clutter specks masked by light precip near radar. --------------------------------------------------------------------------------- 0228-0233Z: Some AP to NW. 2B, 3B !!FLAG!! ----> Flagged only as minor since most of AP is > 150 km 2A,3A,3B !!FLAG!! 0616-0806Z: Light precip with moderate / intense embedded AP (terrible combo!). Some AP removed - most showers left intact. Some showers at far range (>= 150 km) developed holes in coverage due to this partial fix. Overall, this entire period must be flagged. Also, the second tilt precip eating mode was present during this period. 0811Z used in 1C.HDF instead 0801-0806Z. 0821Z: Second trip echo remnant NW of radar - with light precip. ----> Corrected. 0942-1244Z: AP specks - no precip. ----> Corrected. 1501-2351Z: AP specks - no precip. ----> Corrected. NOTE: 0042Z included in 1C.HDF instead of 0032-0037Z. 0811Z included in 1C.HDF instead of 0801-0806Z. *********************************************************************************************** 14 Feb 98: Large shield of precip moves into the radar scope after 16Z from the SW. Widespread moderate to heavy precip w/in this mass of precip. Another huge area of rain nudges into the picture from the S after 22Z. Data Processed: 0001-2355Z Satellite Coincidence: 1516Z(376 km), 1653Z(393 km), 1829Z(627 km), 2006Z(276 km), 2143Z(588 km) QC notes: 0001-1036Z: Various intensities/coverage of AP ----> Corrected 1253-1342Z: AP to NE? Looks kind of like a light, isolated cell, but not a lot of structure to it (vertical or temporal). Some velocity signature, but very disperse. Appears to be clear air echo. ----> Corrected ---------------------------------------------------------- 1702-2355Z: Some lighter precip eliminated...bigger problem, though, is second tilt precip eating ----> Corrected, except for minor flags below. 1B !!FLAG!! 2113-2203Z: A few clutter specks near precip...mostly small and not intense (except 2113Z, which could be borderline major.) *********************************************************************************************** 15 Feb 98: Widespread moderate precip from two large precip masses in early part of the day. By 04Z, the precip mass originally in the S half of the radar scope edges to the NNE and covers almost the entire E half of scope. Light to moderate precip gradually from this system moves out by 11Z, but another batch of light showers develops in the N half of scope between 11-13Z. By 15Z, a convective line forms over the Gulf remains fairly stationary. The convection quickly dies off and residual light precip hangs around until 2357Z. Data Processed: 0001-2357Z Satellite Coincidence: 1540Z(115 km), 1717Z(597 km), 1853Z(500 km), 2030Z(154 km) QC notes: 0001-2357Z: Some lighter precip eliminated, mostly around the fringes of larger precip regions. Also encountered the second tilt precip eating again for much of the day. ----> Corrected, except for flags below 3B !!FLAG!! 0031Z: Small AP speck to NW. Perhaps a trivial flag, but will use 0036Z in 1C.HDF instead. 2B, 3B !!FLAG!! 0101-0121Z: Small, light AP specks. 2B, 3B !!FLAG!! 0126-0325Z: Clutter specks underlying light precip. Flagged minor since I think most of the clutter specks will not appear in L2 products because of the data gap around the radar in these products. 0151Z could be major because of the intense NW speck, though. From 0330-0420Z, the specks are mostly concealed by moderate precip. 2B, 3B !!FLAG!! 0425-0727Z: Precip shaved away at back edge of precip shield. The only way to get it back in was to turn off Z0 and drastically lower H1 and Z1, thus introducing some light AP and a few clutter specks. Many of the clutter specks are very near the radar, though, and will most likely not show up in L2 products. 3B !!FLAG!! 0752-0803Z: Same situation as 0425-0727Z. Using 0808Z in 1C.HDF instead of 0803Z. 2B, 3B !!FLAG!! 1101-1256Z: Light precip forms over radar (even more evident in 2nd tilt images) and clutter near radar is embedded in light precip. Flagged as minor since all clutter is very near radar (L2 shouldn't include it). 3B !!FLAG!! 1406-1420Z: A couple light, small AP specks near radar. 3B !!FLAG!! 1956Z: Small clutter speck to NW near radar. 3B !!FLAG!! 2111Z: Small clutter speck to NW near radar. 2B, 3B !!FLAG!! 2131-2357Z: Light specks of clutter introduced in order to include most of the very light echoes. NOTE: 0036Z included in 1C.HDF instead of 0031Z. 0808Z included in 1C.HDF instead of 0803Z. *********************************************************************************************** 16 Feb 98: Some light precip in NW quadrant between 03-05Z. Scattered light precip moves in near 09Z. By 1030Z, leading edge of a large precip mass moves in from the W/SW. By 15Z, easily 70% of radar scope is covered by moderate to heavy precip. Appears mostly stratiform in N w/ some heavier embedded convective cells to S. This system continues moving ENE and moves out of range after 20Z. Scattered convection moves in from W and NW after 22z. A squall line forms by ~2330Z and moves near the radar. Squall line has trailing stratiform in its northernmost sections. Data Processed: 0002-0654Z 0822-2015Z 2159-2358Z Satellite Coincidence: 1427Z(256 km), 1604Z(453 km), 1740Z(615 km), 1917Z(195 km), 2053Z(725 km) QC notes: 0822-2357Z: Some lighter precip removed by defaults ----> Corrected...remants of a radial spike to NW between ~1730-1902Z is > 150 km. *********************************************************************************************** 17 Feb 98: Squall line at 0009Z near radar takes on a broken cell appearance, then weakens into a mass of mostly stratiform precip as it moves generally to the E. Exits the radar scope after 0330Z. A few scattered cells over the Gulf throughout the rest of the day, otherwise quiet. Data Processed: 0009-2359Z Satellite Coincidence: 1315Z(705 km), 1451Z(207 km), 1628Z(617 km), 1805Z(445 km), 1941Z(274 km) QC notes: 0024-0059Z: AP, sometimes very intense, behind broken squall line. 2A, 3A !!FLAG!! ----> Was able to minimize damage of the intense AP at the furthest ranges, but there appears to be embedded AP closer to radar behind the southern-most portion of the line of precip. These VOSs are greatly improved, but are still flagged because of the suspected embedded AP. 0104Z: AP specks. -----> Corrected. 0111-0116Z: A few AP specks. 3B !!FLAG!! -----> Specks are hard to remove because they appear to be embedded in light precip (see 2nd tilt for evidence of this). 0200-0359Z: Second tilt precip eating. Also light to moderate AP from 0229-0249 and 0329-0359Z. -----> Corrected. 1546-1728Z: Small, shallow cell(?) to the immediate NE of radar. 1B, 2B, 3B !!FLAG!! -----> Looks real, but is less than 700m deep (H1=.7 km wipes it out). Decided to leave out of CZ since much of the clutter had to be brought back in order to get the one cell. Also, because of the data gap around the radar in L2, the cell wouldn't even appear in L2 products until after 1652Z when it's very faint. It seems like reintroducing the clutter would make the product much worse than just leaving out this one lone rogue cell. 1816 & 1855Z: Remnants of a radial spike to NW. ------> Corrected. 2103 & 2152Z: Clutter specks near radar. ------> Corrected. *********************************************************************************************** 18 Feb 98: Light to moderate echoes over Gulf between 17-1739Z. Light to moderate patch of showers in the NW quadrant after 1947Z. Additional bands of showers over Gulf between 1947-2358Z. Data Processed: 0010-1739Z 1947-2358Z Satellite Coincidence: 1339Z(134 km), 1516Z(509 km), 1652Z(592 km), 1829Z(98 km) QC notes: 0237-0246Z: Intense AP speck to SW ------> Corrected. 0504-1502Z: Varying degrees of AP intensity & coverage ------> Corrected. 1700-1739Z: Holes and gaps in light echoes in Gulf ------> Corrected. ---------------------------------------------------------- 2137-2358Z: Holes and gaps in light echoes in Gulf. ------> Corrected, except for flags below 3B, 3A !!FLAG!! 2242,2257, 2302-2317Z: AP specks, moderate to intense at 2312 & 2317Z. Using 2323Z in 1C.HDF. 3B, 3A !!FLAG!! 2343-2358Z: AP specks, more widespread and intense to E at 2353 & 2358Z. ---------------------------------------------------------- NOTE: 2323Z included in 1C.HDF instead of 2302-2317Z. *********************************************************************************************** 19 Feb 98: SW-NE oriented band of moderate to heavy precip moves to E across radar scope from 00-17Z. Some heavier embedded convective elements in this band mostly in the southern sections. A few leftover showers in E half after 17Z. Data Processed: 0003-2359Z Satellite Coincidence: 1227Z(560 km), 1403Z(293 km), 1540Z (629 km), 1717Z(379 km), 1853Z(404 km) QC notes: 0003-0648Z: Light to intense AP, some specks and some large pockets of AP. Also light precip in E early on, then moderate to heavier precip in W and central later in this period. Also, some 2nd tilt precip eliminated after 04Z. ----> Corrected, except for following flags: 2A, 3A !!FLAG!! 0003-0043Z: Light echoes to E impossible to keep intact when trying to remove AP. The echo is light and doesn't have any structure in the second tilt at those ranges, therefore, it's hard to tweak the params to remove the sometimes intense AP and keep the shallow, light precip in the same region. Flagging as major and keeping some precip in the picture. Using 0048Z in 1C.HDF for second half of the first granule. After 0043, the precip weakens enough to be considered negligible, and all AP w/in 150 km can be eliminated. 3A !!FLAG!! 0128-0148Z: Terrible AP to NE that is faintly evident in second tilt (thus, some vertical structure in the eyes of the QC algorithm!). Was able to remove all of the AP w/in 150 km, but also removed some light precip to W. Only a tiny fraction of this precip was w/in 150 km, so it was decided that removing AP was more important. Regardless, using 0153Z in 1C.HDF since the nasty AP ceases at this time. 2B, 3B !!FLAG!! 0440-0628Z: Some light AP to NE possibly w/in 150 km. Further increases of params led to holes in nice band of precip, so this is the compromise that was made! A much improved picture over the first pass CZ, though. --------------------------------------------------------------- 0653-0713Z: 2nd tilt imagery precip eliminated. -----> Corrected --------------------------------------------------------------- 0718-1659Z: Holes and gaps in precip band, also 2nd tilt problem. -----> Corrected holes and gaps, but following flags arise: 2B, 3B !!FLAG!! 0828-1003Z: Some clutter specks embedded in light precip near radar 2A, 3A !!FLAG!! 1008-1139Z: More widespread and intense clutter specks embedded in light precip. What made this period worse was that Z0 had to be turned off for many VOSs because it was shaving precip off the back edges near the radar. Even if Z0 could be turned on, the specks would be a problem. Using 1144Z in 1C.HDF instead of 1134-1139Z. 1B, 2B, 3B !!FLAG!! 1144-1519Z: A few embedded clutter specks. --------------------------------------------------------------- 1709-1945Z: AP specks to E along w/ lighter precip. 1B, 2B, 3B !!FLAG!! -----> Some specks still remain, but they mostly border or are greater than 150 km. Flagged because some specks may be a little less than 150 km. Increasing params further eliminates the light echoes in the SE quadrant. NOTE: Including 0048Z in 1C.HDF instead of 0033-0043Z Including 0153Z in 1C.HDF instead of 0133-0148Z Including 1144Z in 1C.HDF instead of 1134-1139Z *********************************************************************************************** 20 Feb 98: A lone cell to the extreme NE until 0030Z and a light echo over the Gulf near 17Z are the only forms of precip observed. Two great satellite overpasses but no precipitation! Data Processed: 0004-2354Z Satellite Coincidence: 1251Z(22 km), 1427Z(553 km), 1604Z (559 km), 1741Z(5 km) QC notes: 0029-0203Z: Light to moderate AP specks and splotches -----> Corrected 1652-1850Z: Portions of light echo over Gulf removed -----> Corrected 2009-2147Z: Light to moderate AP specks -----> Corrected 2216-2236Z: Light AP specks -----> Corrected 2305Z: Light AP specks -----> Corrected 2345Z: Light AP specks -----> Corrected *********************************************************************************************** 21 Feb 98: Clutter filter applied after 0403Z? Light precip moves in from W after 16Z...some moderate to intense cores w/in precip as it becomes more widespread in NW quadrant. Data Processed: 0004-0034Z 0318-2357Z Satellite Coincidence: 1138Z(425 km), 1315Z(368 km), 1452Z(629 km), 1628Z(306 km), 1805Z(537 km) QC notes: 0004-1146Z: AP, very intense &/or widespread at times -----> Corrected 1255-1423Z: AP specks -----> Corrected 1503Z: light AP specks -----> Corrected ------------------------------------------------------- 1701-2357Z: Lighter precip removed -----> Corrected, except for flags below (specks too difficult to remove w/o taking out substantially more of the light precip): 1B !!FLAG!! 1816Z: Small, light AP speck. 2B, 3B !!FLAG!! 2007-2057Z: Small, scattered AP specks embedded in light precip. 2B, 3B !!FLAG!! 2227-2357Z: Scattered clutter specks near radar as light precip moves near/over. ************************************************************************************************ 22 Feb 98: Huge MCC-like system moves in from west. The convective system has a leading squall line with a couple of bowing segments between 03-05Z. The squall line becomes enveloped in a large shield of moderate to heavy precip by 0530Z. The system continues to move out to the ENE, exhibiting some mesoscale rotation as it leaves the radar scope after Some backwash showers evident thru 1630z, then no precip afterwards. Data Processed: 0002-2359Z Satellite Coincidence: 1202Z(80 km), 1339Z(587 km), 1516Z(518 km), 1652Z(112 km) QC notes: 0133-0459Z: Some lighter precip shaved off the back egdes of convective cells, esp. near radar. 2B, 3B !!FLAG!! ----> Corrected most of the precip shaved off, but some specks of clutter are picked up as light precip moves near the radar. ------------------------------------------------------------- 0614-1659Z: Holes and gaps in lighter precip. ----> Corrected the holes and gaps, but following flags result: 2B, 3B !!FLAG!! 0704-0709Z: Embedded clutter specks near radar. 2A, 3A !!FLAG!! 0714-0814Z: More intense, widespread clutter specks near radar. Had to dramatically decrease params during this time to avoid severe holes in precip. Using 0819Z in 1C.HDF. ------------------------------------------------------------- 2023-2033Z: Clutter speck near radar ----> Corrected NOTE: 0819Z included in 1C.HDF instead of 0804-0814Z. ************************************************************************************************ 23 Feb 98: A few showers over the Gulf after 1530Z. Data Processed: 0009-1654Z Satellite Coincidence: 1050Z(300 km), 1226Z(432 km), 1403Z(621 km), 1540Z(226 km), 1716Z(673 km) QC notes: 0622-1441Z: AP of varying intensities and coverage. ----> Corrected 1654Z: What is this??!! Very weird image right before data gap...since there's satellite coincidence at 1716Z, this VOS is moved to the 'files not in 1CHDF directory'. ************************************************************************************************ 24 Feb 98: Some light to moderate echoes over Gulf after 16Z. Data Processed: 0244-1802Z 1943-2353Z Satellite Coincidence: 1113Z(172 km), 1250Z(610 km), 1427Z(468 km), 1603Z(225 km) QC notes: 0244-1552Z: AP, mostly lighter specks, but some intense AP in places esp. around 1154 & 1204Z. ----> Corrected 1713-2353Z: Light, shallow echoes over Gulf eliminated by default params. 2B, 3B !!FLAG!! ----> The echoes are very shallow and light, so bringing them back in CZ required some light AP specks to be introduced. Much effort was spent trying to find decent params to use, but nothing seemed perfect. 2244Z could be considered a major flag since some spike remants w/ more intense reflectivity values are located near 150 km. *********************************************************************************************** 25 Feb 98: Light showers in the Gulf 00~02Z. Scattered showers and small convective cells develop N and W of KHGX radar 2230~2359Z. A moisture rich flow is coming from the South in advance of the severe event on Feb 26. Data Processed: 0003-2359Z Satellite Coincidence: 1001Z(184km), 1137Z(487km), 1314Z(603km), 1450Z(140km) QC notes: 2B,3B !!FLAG!! 0003-0249Z: Light, shallow showers removed by default QC params. Most precip reinstated. Some AP was reinstated with the showers. Tuning dBZ_Noise removed a large portion of the AP, but not all of it. A large area of moderate to intense AP is beyond the 150 km range at 0240Z and 0249Z. Because of the far range, only minor flags are given. Some minor AP close to the radar in all VOSs cannot be removed due to presence of extremely shallow showers. Therefore, this entire period is flagged. 0259-1723Z: AP of varying intensities and coverage - no precip. ----> Corrected 2349-2354Z: Second trip echo in second tilt images. ----> Corrected within 150 km range. *********************************************************************************************** 26 Feb 98: An incredible severe weather day for south Texas. The day begins with scattered shower activity as a low-level moisture rich flow spreads North from the Gulf. By ~0330Z, the leading edge of a large squall line MCS appears at far range (200 km) to the NW of radar. By ~06Z, an intense squall line with reflectivities approaching 55 dBZ is approaching from the NW. The squall line and trailing heavy stratiform shield are moving ESE while embedded cells within the squall line move ENE. By ~10Z, a large area of heavy rain with embedded 50+ dBZ cells pushes closer to KHGX radar, but remains N and W. By ~12Z, Large, intense (50-60 dBZ) cells move directly over radar in a bow echo pattern while a larger area of heavy stratiform rain passes N of radar. These cells continue to intensify E of radar and display 55+ dBZ reflectivities and bow echo pattern. This entire severe event has a classic "V" shape appearance. The main activity exits scope by ~15Z with a few isolated convective cells, and light showers behind (to the west of) the main squall line. TRMM PR passes N of KHGX at 1025Z (257km) during this event. Data Processed: 0004-2354Z Satellite Coincidence: 0848Z(621km), 1025Z(257km), 1201Z(625km), 1338Z(408km), 1515Z(348km) QC notes: 0004-0339Z: Shallow precip near radar removed by default QC params. Most showers reinstated. A few very minor clutter specks were brought back with the showers but they were not major enough for flagging. One VOS has second trip echo and is flagged below. ----> Corrected except for flag below 3B !!FLAG!! 0240Z: Second trip echo NW of radar could not be removed due to presence of light precip. 0531-0626Z: Shallow precip near radar removed by default QC params. Also, some holes in light precip ahead and behind squall line. Most showers reinstated. A few extremely small,shallow light showers near radar were not reinstated so that clutter specks would be suppressed. ----> Corrected. -------------------------------------------------------------------------------- 0636-1417Z: Large holes in light precip + second tilt precip missing. The only way to bring base scan precip back was to "turn off" Z0 and Z1. When these parameters are turned off, the showers are reinstated but so is clutter. See flags below. ----> All precip reinstated - some clutter reinstated also. 3B !!FLAG!! 0641-0646Z: Minor clutter specks brought back with light precip. 2B,3B !!FLAG!! 0656-0731Z: Minor clutter specks brought back with light precip. 1B,2B,3B !!FLAG!! 0741-0816Z: Minor clutter specks brought back with light precip. 1B,2B !!FLAG!! 0831-0851Z: Minor clutter specks brought back with light precip. Note: Many other VOSs in this time period contain some clutter specks but they are masked by moderate / heavy precip. In my opinion, there is no need to flag these VOSs. ------------------------------------------------------------------------------- 1920Z: What is this ?! VOS is corrupt. VOS wiped clean - no precip at this time. ----> Corrected. ************************************************************************************************** 27 Feb 98: No precip during the first half of day. A light precip shield remains NW of radar at far range from 16Z ~ 18Z. Light showers (~10 dBZ) develop NE and NW of radar ~18Z. By ~19Z, showers (mainly < 30 dBZ) develop throughout entire radar scope and propogate SW to NE. A few cells (~40 dBZ) are embedded within much lighter showers during the 23Z hour. Unfortunately, the two excellent TRMM overpass times (noted below) do not contain any precip. Data Processed: 0000-0334Z 0759-2359Z Satellite Coincidence: 0912Z(67km!), 1049Z(536km), 1226Z(574km), 1402Z(39km!) QC notes: 0006Z: Second trip echo in second tilt image (does not effect base tilt). ----> Corrected. 0150-1547Z: AP specks - no precip. ----> Corrected (easily) 1556Z: AP specks surrounding radar while light precip is evident beyond 150 km range. VOS wiped clean. The missing precip will have no effect on L2 products. ----> Corrected. 1559-1731Z: Light precip NW of radar, and light AP specks SE of radar in Gulf. Both precip and AP specks are *outside* of 150 km range. There is no need to reprocess for this particular problem. 1608-1956Z: Second tilt precip removed by default QC params. H3 too high. ----> Corrected - all precip restored. Note: A few VOSs within this period have AP specks *outside* of the 150 km range in the Gulf. There was no attempt to remove this AP due to the presence of light precip. The AP will not have any effect on L2 products because of the far range. 2001Z: Clutter speck NW of radar - also, 2nd tilt precip (virga?) removed by default QC params. ----> Corrected. 2006-2041Z: Second tilt precip (virga?) removed by default QC params. H3 too high. ----> Corrected - all precip restored. 2046-2359Z: Precip missing in base tilt near radar - also, second tilt precip removed by default qc params. ----> Corrected - all precip restored. Unfortunately, some clutter specks were also restored with the precip in the base scan. Overall, H3=0 and Z0=-30 did an excellent job in bringing back precip. The following VOSs are flagged due to clutter. Note: 2214-2219Z AP speck in Gulf *outside* of 150 km range. This was confirmed with L2 conv/strat product, therefore not flagged. 3B !!FLAG!! 2121Z: Minor clutter specks brought back with light precip. 2B,3B !!FLAG!! 2131-2141Z: Minor clutter specks brought back with light precip. 3B !!FLAG!! 2324Z: Minor clutter specks brought back with light precip. *********************************************************************************************** 28 Feb 98: Widepsread shower / t-shower activity mainly over land (just N of radar) from 00-04Z. Precip is mainly < 30 dBZ. From 04~07Z, showers become scattered in coverage and much lighter in intensity while remaining N of radar. A large shield of showers (max dBZ = 30) enters scope from the NW ~12Z. These showers move NE while entire line of showers sags to the SE toward radar. By ~21Z, most shower activity remains N of radar and weakens, while an additional small area of showers develops in Gulf. 0717Z: Clutter filter turned off 0847Z: Clutter filter turned back on (the AP was intense) Data Processed: 0004-2358Z Satellite Coincidence: 0800Z(479km), 0936Z(338km), 1113Z(630km) 1250Z(337km), 1426Z(482km) QC notes: ----------------------------------------------------------------- 0004-0144Z: Precip removed near radar in base tilt, also 2nd tilt precip removed. ----> All precip restored in base and 2nd tilt, but clutter and light AP specks are also restored in all VOSs. Therefore, entire period must be flagged. 2B,3B !!FLAG!! 0004-0039Z: Clutter specks embedded in precip near radar. AP specks in Gulf at various ranges. 2A !!FLAG!! 0044Z: Intense AP specks in Gulf with precip near radar. 2B,3B !!FLAG!! 0049-0144Z: Clutter specks embedded in precip near radar. AP specks in Gulf at various ranges. -------------------------------------------------------------------- 2A,2B,3A,3B 0149-0453Z: Light/Moderate/Intense AP specks and patches at varying ranges !!FLAG!! with light to moderate precip. Also, 2nd tilt precip removed. ----> 2nd tilt precip restored, but AP cannot be entirely removed from the base scans due to presence of light precip. Light to intense AP remains in images. A few minor showers were removed in this correction attempt. Entire period must be flagged. --------------------------------------------------------------------- 0458-0617Z: Moderate/Intense AP within 150 km range, with very minor area of light precip *beyond* 150 km range. All VOSs were wiped clean. The removal of real echo beyond 150 km has no effect on L2 products. ----> Corrected. ---------------------------------------------------------------------- 0622-1028Z: Moderate/Intense AP surrounding radar - no precip ----> Corrected. ---------------------------------------------------------------------- 1033-1105: Moderate/Intense AP within 150 km range, with very minor area of light precip *beyond* 150 km range. All VOSs were wiped clean. The removal of real echo beyond 150 km has no effect on L2 products. ----> Corrected. ----------------------------------------------------------------------- 1110-1141Z: Moderate/Intense AP surrounding radar - no precip ----> Corrected. ---------------------------------------------------------------------- 1146-1211Z: Moderate/Intense AP within 150 km range, with very minor area of light precip *beyond* 150 km range. All VOSs were wiped clean. The removal of real echo beyond 150 km has no effect on L2 products. ----> Corrected. ----------------------------------------------------------------------- 1216-1421Z: Light/Moderate AP surrounding radar - with shower activity approaching from the NW. Also, 2nd tilt precip removed by default qc params. ----> Some (but not all) of the AP has been removed. Second tilt precip has been restored. AP cannot be removed due to presence of light /moderate precip NW of radar. Periods where AP could not be removed are flagged below. 1A,2A,3A !!FLAG!! 1216-1328Z: Moderate/Intense AP could not be removed due to presence of precip. Some AP has widespread coverage. 1B,2B,3B !!FLAG!! 1333-1426Z: Light AP could not be removed due to precence of precip. ------------------------------------------------------------------------- 1431-2358Z: Some lighter precip removed, also 2nd tilt precip eating. A few VOSs between 1827-1937 and 1952-2047 also had the precip near radar cleared out in a solid circle about 10 km radius around the radar. ----> Corrected, except for flags below for clutter specks. Note that some major flags are used, but they may not actually be major problems if the clutter specks are located within the ~10 km data gap radius in L2 products. 2B, 3B !!FLAG!! 1527-1617Z: Clutter speck NW of radar near light precip. 2B, 3B !!FLAG!! 1727&1757Z: Clutter speck NW of radar near light precip. 2B, 3B !!FLAG!! 1807-1817Z: Clutter speck NW of radar near light precip. 2A,2B,3A,3B !!FLAG!! 1827-1937Z: Intense clutter specks near radar beneath light precip. Using 1942Z in 1C.HDF. 2A,2B,3A,3B !!FLAG!! 1947-2057Z: Intense clutter specks near radar beneath light precip. 3B !!FLAG!! 2137Z: Clutter speck near radar. Note: 1942Z included in 1C.HDF instead of 1932-1937Z. *****************************************************************************************************